Mobile communication system

ABSTRACT

A communication system has three types of cells including, in addition to an MBMS dedicated cell, a unicast cell to and from which a mobile terminal can transmit and receive individual communication data, and a unicast/MBMS-mixed cell which can provide both a service provided by the unicast cell and a service provided by the MBMS dedicated cell. While receiving the broadcast type data transmitted from the MBMS dedicated cell, the mobile terminal makes a notification of an MBMS receiving state via the unicast cell or the unicast/MBMS-mixed cell to transmit information for identifying the MBMS dedicated cell, and the communication system transmits a paging signal to the mobile terminal currently receiving the broadcast type data transmitted from the MBMS dedicated cell on the basis of a tracking area (Tracking Area) in which the mobile terminal is tracked, the tracking area being determined on the basis of the information transmitted.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 12/808,960filed Jun. 17, 2010, the entire content of which is incorporated hereinby reference. U.S. application Ser. No. 12/808,960 is a National Phaseof PCT/JP08/03730 filed Dec. 12, 2008 and claims priority to JapanesePatent Application No. 2007-324525 filed Dec. 17, 2007.

FIELD OF THE INVENTION

The present invention relates to a mobile communication system in whicha base station carries out radio communications with a plurality ofmobile terminals. More particularly, it relates to a mobilecommunication system that can provide a broadcast type multimediaservice (MBMS: Multimedia Broadcast Multicast Service) for mobileterminals.

BACKGROUND OF THE INVENTION

Commercial services which employ a W-CDMA (Wideband Code divisionMultiple Access) method which is included in communication methodscalled a third generation were started in Japan since 2001. Furthermore,a service with HSDPA (High Speed Down Link Packet Access) whichimplements a further improvement in the speed of data transmission usingdownlinks (a dedicated data channel and a dedicated control channel) byadding a channel for packet transmission (HS-DSCH: High Speed-DownlinkShared Channel) to the downlinks has been started. In addition, an HSUPA(High Speed Up Link Packet Access) method has also been standardized inorder to further speed up uplink data transmission. The W-CDMA is acommunication method which was determined by the 3GPP (3rd GenerationPartnership Project) which is the organization of standardization ofmobile communication systems, and the technical specification of therelease 7 has been being organized currently.

In the 3GPP, as a communication method different from the W-CDMA, a newcommunication method having a wireless section, which is referred to as“Long Term Evolution” (LTE), and a whole system configuration includinga core network, which is referred to as “System Architecture Evolution”(SAE), has also been studied. The LTE has an access method, a radiochannel structure, and protocols which are completely different fromthose of the current W-CDMA (HSDPA/HSUPA). For example, while the W-CDMAuses, as its access method, code division multiple access (Code DivisionMultiple Access), the LTE uses, as its access method, OFDM (OrthogonalFrequency Division Multiplexing) for the downlink direction and usesSC-FDMA (Single Career Frequency Division Multiple Access) for theuplink direction. Furthermore, while the W-CDMA has a bandwidth of 5MHz, the LTE enables each base station to select one bandwidth fromamong bandwidths of 1.4/3/5/10/15/20 MHz. In addition, the LTE does notinclude a circuit switching method, unlike the W-CDMA, but uses only apacket communication method.

According to the LTE, because a communication system is configured usinga new core network different from a core network (GPRS) in the W-CDMA,the communication system is defined as an independent radio accessnetwork which is separate from a W-CDMA network. Therefore, in order todistinguish from a communication system which complies with the W-CDMA,in a communication system which complies with the LTE, a base station(Base station) which communicates with a mobile terminal (UE: UserEquipment) is referred to as eNB (E-UTRAN NodeB), and a base stationcontrol apparatus (Radio Network Controller) which performs exchange ofcontrol data and user data with a plurality of base stations is referredto as an EPC (Evolved Packet Core) (may be called aGW: Access Gateway).This communication system which complies with the LTE provides a yunicast (Unicast) service and an E-MBMS service (Evolved MultimediaBroadcast Multicast Service). An E-MBMS service is a broadcast typemultimedia service, and simply may be referred to as an MBMS. Alarge-volume broadcast content, such as news, a weather forecast, or amobile broadcasting content, is transmitted to a plurality of mobileterminals. This service is also referred to as a point-to-multipoint(Point to Multipoint) service.

Matters currently determined in the 3GPP and regarding a wholearchitecture (Architecture) in an LTE system are described in nonpatentreference 1. The whole architecture (chapter 4 of nonpatent reference 1)will be explained with reference to FIG. 1. FIG. 1 is an explanatorydrawing showing the configuration of a communication system using an LTEmethod. In FIG. 1, if a control protocol (e.g., RRC (Radio ResourceManagement)) and a user plane (e.g., PDCP: Packet Data ConvergenceProtocol, RLC: Radio Link Control, MAC: Medium Access Control, PHY:Physical layer) for a mobile terminal 101 are terminated at a basestation 102, E-UTRAN (Evolved Universal Terrestrial Radio Access) isconstructed of one or more base stations 102. Each base station 102carries out scheduling (Scheduling) and transmission of a paging signal(Paging Signaling, which is also referred to as paging messages (pagingmessages)) which is transmitted thereto from an MME 103 (MobilityManagement Entity). The base stations 102 are connected to one anothervia X2 interfaces. Furthermore, each base station 102 is connected to anEPC (Evolved Packet Core) via an S1 interface. More specifically, eachbase station is connected to an MME 103 (Mobility Management Entity) viaan S1_MME interface, and is also connected to an S-GW 104 (ServingGateway) via an S1_U interface. Each MME 103 distributes a paging signalto one or more base stations 102. Furthermore, each MME 103 carries outmobility control (Mobility control) of an idle state (Idle State). EachS-GW 104 carries out transmission and reception of user data to and fromone or more base stations 102.

Matters currently determined in the 3GPP and regarding a frame structurein a LTE system are described in nonpatent reference 1 (Chapter 5). Thecurrently determined matters will be explained with reference to FIG. 2.FIG. 2 is an explanatory drawing showing the configuration of a radioframe for use in a communication system using an LTE method. In FIG. 2,one radio frame (Radio frame) has a time length of 10 ms. Each radioframe is divided into ten equal-sized subframes (Subframes). Eachsubframe is divided into two equal-sized slots (slots). A downlinksynchronization channel (Downlink Synchronization Channel: SCH) isincluded in each of the 1st (#0) and 6th subframes (#5) of each frame.Synchronization signals include a primary synchronization channel(Primary Synchronization Channel: P-SCH) and a secondary synchronizationchannel (Secondary Synchronization Channel: S-SCH). Multiplexing of achannel used for MBSFN (Multimedia Broadcast multicast service SingleFrequency Network) and a channel used for other than MBSFN is carriedout for each subframe. Hereafter, a subframe used for MBSFN transmissionis referred to as an MBSFN subframe (MBSFN subframe). In nonpatentreference 2, an example of signaling at the time of allocation of MBSFNsubframes is described. FIG. 3 is an explanatory drawing showing theconfiguration of an MBSFN frame. In FIG. 3, MBSFN subframes areallocated to each MBSFN frame (MBSFN frame). An MBSFN frame cluster(MBSFN frame Cluster) is scheduled. The repetition period (RepetitionPeriod) of an MBSFN frame cluster is allocated.

Matters currently determined in the 3GPP and regarding a channelstructure in an LTE system are described in nonpatent reference 1.Physical channels (Physical channels) (chapter 5 of nonpatentreference 1) will be explained with reference to FIG. 4. FIG. 4 is anexplanatory drawing explaining physical channels for use in acommunication system using an LTE method. In FIG. 4, a physicalbroadcast channel 401 (Physical Broadcast channel: PBCH) is a downlinkchannel which is transmitted from a base station 102 to a mobileterminal 101. A BCH transport block (transport block) is mapped ontofour subframes during a 40-ms time period. There is no clear signalinghaving a timing of 40 ms. A physical control channel format indicatorchannel 402 (Physical Control format indicator channel: PCFICH) istransmitted from the base station 102 to the mobile terminal 101. ThePCFICH informs the number of OFDM symbols used for PDCCHs from the basestation 102 to the mobile terminal 101. The PCFICH is transmitted ineach subframe. A physical downlink control channel 403 (Physicaldownlink control channel: PDCCH) is a downlink channel transmitted fromthe base station 102 to the mobile terminal 101. The PDCCH informsresource allocation (allocation), HARQ information about a DL-SCH (adownlink shared channel which is one of transport channels shown in FIG.5), and a PCH (paging channel which is one of the transport channelsshown in FIG. 5). The PDCCH carries an uplink scheduling grant (UplinkScheduling Grant). The PDCCH also carries ACK/Nack which is a responsesignal showing a response to uplink transmission. A physical downlinkshared channel 404 (Physical downlink shared channel: PDSCH) is adownlink channel transmitted from the base station 102 to the mobileterminal 101. A DL-SCH (downlink shared channel) which is a transportchannel is mapped onto the PDSCH. A physical multicast channel 405(Physical multicast channel: PMCH) is a downlink channel transmittedfrom the base station 102 to the mobile terminal 101. An MCH (multicastchannel) which is a transport channel is mapped onto the PMCH.

A physical uplink control channel 406 (Physical Uplink control channel:PUCCH) is an uplink channel transmitted from the mobile terminal 101 tothe base station 102. The PUCCH carries ACK/Nack which is a responsesignal (response) which is a response to downlink transmission. ThePUCCH carries a CQI (Channel Quality indicator) report. The CQI isquality information showing either the quality of received data orcommunication channel quality. A physical uplink shared channel 407(Physical Uplink shared channel: PUSCH) is an uplink channel transmittedfrom the mobile terminal 101 to the base station 102. A UL-SCH (anuplink shared channel which is one of the transport channels shown inFIG. 5) is mapped onto the PUSCH. A physical HARQ indicator channel 408(Physical Hybrid ARQ indicator channel: PHICH) is a downlink channeltransmitted from the base station 102 to the mobile terminal 101. ThePHICH carries ACK/Nack which is a response to uplink transmission. Aphysical random access channel 409 (Physical random access channel:PRACH) is an uplink channel transmitted from the mobile terminal 101 tothe base station 102. The PRACH carries a random access preamble (randomaccess preamble).

The transport channels (Transport channels) (chapter 5 of nonpatentreference 1) will be explained with reference to FIG. 5. FIG. 5 is anexplanatory drawing explaining the transport channels for use in acommunication system using an LTE method. Mapping between downlinktransport channels and downlink physical channels is shown in FIG. 5A.Mapping between uplink transport channels and uplink physical channelsis shown in FIG. 5B. In the downlink transport channels, a broadcastchannel (Broadcast channel: BCH) is broadcast to all the base stations(cell). The BCH is mapped onto a physical broadcast channel (PBCH).Retransmission control with HARQ (Hybrid ARQ) is applied to a downlinkshared channel (Downlink Shared channel: DL-SCH). Broadcasting to allthe base stations (cell) can be carried out. Dynamic or semi-static(Semi-static) resource allocation is supported. Semi-static resourceallocation is also referred to as persistent scheduling (PersistentScheduling). DRX (Discontinuous reception) by a mobile terminal issupported in order to achieve low power consumption of the mobileterminal. The DL-SCH is mapped onto a physical downlink shared channel(PDSCH). A paging channel (Paging channel: PCH) supports DRX by a mobileterminal in order to enable the mobile terminal to achieve low powerconsumption. Broadcasting to all the base stations (cell) is requested.Mapping onto either a physical resource such as a physical downlinkshared channel (PDSCH) which can be dynamically used for traffic, or aphysical resource such as a physical downlink control channel (PDCCH)which is another control channel is carried out. A multicast channel(Multicast channel: MCH) is used for the broadcasting to all the basestations (cell). SFN combining of MBMS services (MTCH and MCCH) inmulti-cell transmission is supported. Semi-static resource allocation issupported. The MCH is mapped onto a PMCH.

Retransmission control with HARQ (Hybrid ARQ) is applied to an uplinkshared channel (Uplink Shared channel: UL-SCH). Dynamic or semi-static(Semi-static) resource allocation is supported. A UL-SCH is mapped ontoa physical uplink shared channel (PUSCH). A random access channel(Random access channel: RACH) shown in FIG. 5B is limited to controlinformation. There is a risk of collision. The RACH is mapped onto aphysical random access channel (PRACH). HARQ will be explainedhereafter.

HARQ is a technology of improving the communication quality of atransmission line by using a combination of automatic retransmission(Automatic Repeat reQuest) and error correction (Forward ErrorCorrection). Retransmission provides an advantage of making an errorcorrection function be effective also for a transmission line whosecommunication quality varies. Particularly, when performingretransmission, combining the results of reception of first-timetransmission and the results of reception of retransmission provides afurther improvement in the quality. An example of a retransmissionmethod will be explained. When a receive side cannot decode receiveddata correctly (when a CRC Cyclic Redundancy Check error occurs(CRC=NG)), the receive side transmits “Nack” to the transmit side. Whenreceiving “Nack”, the transmit side retransmits the data. In contrast,when the receive side can decode the received data correctly (when noCRC error occurs (CRC=OK)), the receive side transmits “Ack” to thetransmit side. When receiving “Ack”, the transmit side transmits thenext data. There is “chase combining” (Chase Combining) as an example ofa HARQ method. The chase combining is a method of transmitting the samedata sequence at the time of first-time transmission and at the time ofretransmission, and, when performing retransmission, combining the datasequence at the first-time transmission and the data sequence at theretransmission to improve the gain. This is based on an idea that evenif the first-time transmission data has an error, the first-timetransmission data partially includes correct data, and therefore thedata can be transmitted with a higher degree of precision by combiningthe correct portion of the first-time transmission data and theretransmission data. Furthermore, there is IR (Incremental Redundancy)as another example of the HARQ method. The IR is a method of increasingthe degree of redundancy with a combination with the first-timetransmission by transmitting a parity bit at the time of retransmissionto improve the quality by using an error correction function.

Logical channels (Logical channels) (chapter 6 of nonpatent reference 1)will be explained with reference to FIG. 6. FIG. 6 is an explanatorydrawing explaining logical channels for use in a communication systemusing an LTE method. Mapping between downlink logical channels anddownlink transport channels is shown in FIG. 6A. Mapping between uplinklogical channels and uplink transport channels is shown in FIG. 6B. Abroadcast control channel (Broadcast control channel: BCCH) is adownlink channel for broadcast system control information. The BCCHwhich is a logical channel is mapped onto either a broadcast channel(BCH) which is a transport channel, or a downlink shared channel(DL-SCH). A paging control channel (Paging control channel: PCCH) is adownlink channel for transmitting a paging signal. The PCCH is used whenthe network does not know the cell location of a mobile terminal. ThePCCH which is a logical channel is mapped onto a paging channel (PCH)which is a transport channel. A common control channel (Common controlchannel: CCCH) is a channel for transmission control information betweena mobile terminal and a base station. The CCCH is used when the mobileterminal does not have RRC connection (connection) between the mobileterminal and the network. Whether to dispose the CCCH for downlink isnot decided at this time. In the uplink direction, the CCCH is mappedonto an uplink shared channel (UL-SCH) which is a transport channel.

A multicast control channel (Multicast control channel: MCCH) is adownlink channel for point-to-multipoint transmission. The channel isused for transmission of MBMS control information for one or some MTCHsfrom the network to mobile terminals. The MCCH is used only for a mobileterminal currently receiving an MBMS. The MCCH is mapped onto either adownlink shared channel (DL-SCH) which is a transport channel, or amulticast channel (MCH). A dedicated control channel (Dedicated controlchannel: DCCH) is a channel for transmitting dedicated controlinformation between a mobile terminal and the network. The DCCH ismapped onto an uplink shared channel (UL-SCH) in the uplink, and ismapped onto a downlink shared channel (DL-SCH) in the downlink. Adedicated traffic channel (Dedicate Traffic channel: DTCH) is a channelof point-to-point communications to each mobile terminal fortransmission of user information. The DTCH exists for both the uplinkand the downlink. The DTCH is mapped onto an uplink shared channel(UL-SCH) in the uplink, and is mapped onto a downlink shared channel(DL-SCH) in the downlink. A multicast traffic channel (Multicast Trafficchannel: MTCH) is a downlink channel for transmission of traffic datafrom the network to a mobile terminal. The MTCH is used only for amobile terminal currently receiving an MBMS. The MTCH is mapped ontoeither a downlink shared channel (DL-SCH) or a multicast channel (MCH).

Matters currently determined in the 3GPP and regarding an E-MBMS serviceare described in nonpatent reference 1. The definitions of termsregarding E-MBMS (chapter 15 of nonpatent reference 1) will be explainedwith reference to FIG. 7. FIG. 7 is an explanatory drawing forexplaining a relationship between an MBSFN synchronization area andMBSFN areas. In FIG. 7, the MBSFN synchronization area 701 (MultimediaBroadcast multicast service Single Frequency Network SynchronizationArea) is a network area in which all the base stations can perform MBSFN(Multimedia Broadcast Multicast service Single Frequency Network)transmission in synchronization with one another. The MBSFNsynchronization area includes one or more MBSFN areas (MBSFN Areas) 702.In one frequency layer (frequency layer), each base station can belongonly to one MBSFN synchronization area. Each MBSFN area 702 (MBSFN Area)consists of a group of base stations (cell) included in the MBSFNsynchronization area of the network. The base stations (cell) in theMBSFN synchronization area may construct a plurality of MBSFN areas.

The logical architecture (Logical Architecture) of E-MBMS (chapter 15 ofnonpatent reference 1) will be explained with reference to FIG. 8. FIG.8 is an explanatory drawing explaining the logical architecture (LogicalArchitecture) of E-MBMS. In FIG. 8, a multi-cell/multicast coordinationentity 801 (Multi-cell/multicast Coordination Entity: MCE) is a logicalentity. The MCE 801 allocates radio resources to all the base stationsin an MBSFN area in order to carry out multi-cell MBMS transmission(multi-cell MBMS transmission). The MCE 801 makes a decision about thedetails of radio configuration (e.g., a modulation method and a code) inaddition to the allocation of the radio resources in time and/or infrequency. An E-MBMS gateway 802 (MBMS GW) is a logical entity. TheE-MBMS gateway 802 is located between an eBMSC and base stations, andhas a main function of transmitting and broadcasting an MBMS service toeach of the base stations according to a SYNC protocol. An M3 interfaceis a control interface (Control Plane Interface) between the MCE 801 andthe E-MBMS gateway 802. An M2 interface is a control interface betweenthe MCE 801 and an eNB 102. An M1 interface is a user data interface(User Plane Interface) between the E-MBMS gateway 802 and the eNB 803.

The architecture (Architecture) of E-MBMS (chapter 15 of nonpatentreference 1) will be explained. FIG. 9 is an explanatory drawingexplaining the architecture (Architecture) of E-MBMS. As to thearchitecture of E-MBMS, two examples are considered as shown in FIGS. 9Aand 9B. Cells (15 of nonpatent reference 1) of MBMS will be explained.In an LTE system, there is an MBMS dedicated cell (base station) (MBMSdedicated cell) and an MBMS/Unicast-mixed cell (MBMS/Unicast-mixed cell)which can carry out both an MBMS service and a unicast service. An MBMSdedicated cell will be explained. Features in a case in which the MBMSdedicated cell belongs to a frequency layer dedicated to MBMStransmission will be described hereafter. Hereinafter, the MBMStransmission dedicated frequency layer is also referred to as an MBMSdedicated cell frequency layer. An MTCH (multicasting traffic channel)and an MCCH (multicast control channel) which are both downlink logicalchannels are mapped onto either an MCH (multicast channel) which is adownlink transport channel or a DL-SCH (downlink shared channel) inpoint-to-multipoint transmission. No uplink exists in the MBMS dedicatedcell. Furthermore, transmission and reception of unicast data cannot becarried out within the MBMS dedicated cell. Furthermore, no countingmechanism is set up. Whether to provide a paging signal (Pagingmessages) in the MBMS transmission dedicated frequency layer has notbeen decided.

Next, an MBMS/Unicast-mixed cell will be explained. Features in a casein which the MBMS/Unicast-mixed cell does not belong to the MBMStransmission dedicated frequency layer will be described hereafter. Afrequency layer other than the MBMS transmission dedicated frequencylayer is referred to as a “unicast/mixed frequency layer”. An MTCH andan MCCH which are both downlink logical channels are mapped onto eitheran MCH which is a downlink logical channel or a DL-SCH inpoint-to-multipoint transmission. In the MBMS/Unicast-mixed cell, bothtransmission of unicast data and transmission of MBMS data can becarried out.

MBMS transmission (chapter 15 of nonpatent reference 1) will beexplained. The MBMS transmission in an LTE system supports single-celltransmission (Single-cell transmission: SC transmission) and multi-celltransmission (multi-cell transmission: MC transmission). An SFN (Singlefrequency Network) operation is not supported in the single-celltransmission. Furthermore, an SFN operation is supported in themulti-cell transmission. Transmission of an MBMS is synchronized in anMBSFN (Multimedia Broadcast multicast service Single Frequency Network)area. SFN combining (Combining) of MBMS services (MTCH and MCCH) in themulti-cell transmission is supported. An MTCH and an MCCH are mappedonto an MCH in point-to-multipoint transmission. Scheduling is carriedout by an MCE.

The structure (Structure) of a multicast control channel (MCCH) (Chapter15 of nonpatent reference) will be explained. A broadcast controlchannel (BCCH) which is a downlink logical channel shows scheduling ofone or two primary multicast control channels (Primary MCCH: P-MCCH). AP-MCCH for single-cell transmission is mapped onto a DL-SCH (downlinkshared channel). A P-MCCH for multi-cell transmission is mapped onto anMCH (multicast channel). In a case in which a secondary multicastcontrol channel (Secondary MCCH: S-MCCH) is mapped on an MCH, theaddress of the secondary multicast control channel (S-MCCH) can be shownby using a primary multicast control channel (P-MCCH). Although abroadcast control channel (BCCH) shows a resource of a primary multicastcontrol channel (P-MCCH), it does not show any available service.

Matters currently determined in the 3GPP and regarding paging aredescribed in nonpatent reference 1 (chapter 10). A paging group uses anL1/L2 signaling channel (PDCCH). A precise identifier (UE-ID) of amobile terminal can be checked on a paging channel (PCH).

-   [Nonpatent reference 1] 3GPP TS36.300 V8.2.0-   [Nonpatent reference 2] 3GPP R1-072963-   [Nonpatent reference 3] 3GPP R1-080073-   [Nonpatent reference 4] 3GPP R2-080463-   [Nonpatent reference 5] 3GPP R2-075570-   [Nonpatent reference 6] 3GPP TS36.211 V8.4.0-   [Nonpatent reference 7] 3GPP TS36.331 V8.3.0-   [Nonpatent reference 8] 3GPP TS36.306 V8.2.0

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Problems to be solved by the present invention will be explained. Innonpatent reference 1, it is not decided whether to make a paging signalexist in an MBMS transmission dedicated frequency layer. Therefore, amethod of and a mobile communication system for transmitting a pagingsignal to a mobile terminal which is currently receiving an MBMS servicein an MBMS transmission dedicated frequency layer have not been decidedyet. It is therefore an object of the present invention to provide amethod of and a mobile communication system for transmitting a pagingsignal to a mobile terminal which is currently receiving an MBMS servicein an MBMS transmission dedicated frequency layer.

Furthermore, in a case of transmitting a paging signal in an MBMStransmission dedicated frequency layer, a mobile terminal which hasreceived the paging signal needs to answer this signal. However, nouplink exists in an MBMS dedicated cell. Therefore, the mobile terminalneeds to transmit a response to the paging signal to either a unicastcell or an MBMS/Unicast-mixed cell. It is therefore another object ofthe present invention to provide a method of enabling a mobile terminalwhich has received a paging signal to transmit a response to the pagingsignal to either a unicast cell or an MBMS/Unicast-mixed cell, and amobile communication system which enables the method to be implementedtherein.

Furthermore, the details of a method of transmitting a paging messagehas not been established also for a mobile terminal being in an idlestate (Idle State) at a frequency which is not in an MBMS transmissiondedicated frequency layer (in a unicast/mixed frequency layer).Nonpatent reference 1 discloses that a PCH is mapped onto either a PDSCHor a PDCCH. Nonpatent reference 1 also discloses that a paging groupuses an L1/L2 signaling channel (a PDCCH) and that a precise identifier(UE-ID) of a mobile terminal can be found on a PCH. In contrast,nonpatent reference 1 does not disclose how mobile terminals are dividedinto paging groups, and how a PCH is informed. Furthermore, nonpatentreference 1 does not disclose how a mobile terminal being in an idlestate carries out discontinuous reception. It is therefore a furtherobject of the present invention to provide the details of a method oftransmitting a paging signal to a mobile terminal being in an idle statein a unicast/mixed frequency layer, and a mobile communication systemwhich enables the method to be implemented therein.

Furthermore, nonpatent reference 1 discloses existence of an MBMStransmission dedicated frequency layer, and existence and features of anMBMS dedicated cell. In contrast, nonpatent reference 1 does notdisclose a method of enabling a mobile terminal to move to an MBMStransmission dedicated frequency layer and a method of selecting adesired service. In addition, although existence of a plurality of MBSFNareas in an MBMS transmission dedicated frequency layer has beendebated, nonpatent reference 1 does not disclose a method ofmultiplexing MBSFN areas. It is therefore another object of the presentinvention to provide a method of multiplexing MBSFN areas. It is afurther object of the present invention to provide a method of selectinga desired service in an MBMS transmission dedicated frequency layeraccording to the multiplexing method, and a mobile communication systemwhich enables the method to be implemented therein.

Furthermore, no uplink exists in abase station dedicated to MBMS. Evenwhen a mobile terminal moves, and a base station from which the mobileterminal can receive a downlink (a downlink signal or a downlink radiowave) changes and/or the best base station (cell) (providing the highestreceived power) included in the base stations from which the mobileterminal can receive the downlink changes, the mobile terminal has nomeans of informing to any base station dedicated to MBMS to that effect.A problem is therefore that in an MBMS transmission dedicated frequencylayer which consists of base stations dedicated to MBMS, the managementof mobility of mobile terminals cannot be carried out with theconfiguration of a conventional mobile communication system and with aconventional communication method. It is therefore another object of thepresent invention to provide a method of enabling the management ofmobility of mobile terminals even in an MBMS transmission dedicatedfrequency layer which consists of base stations dedicated to MBMS, and amobile communication system which enables the method to be implementedtherein.

Furthermore, a mobile terminal needs to carry out a measurement(measurement) at fixed periods (cycles) in a unicast/mixed frequencylayer. The length of each fixed period is informed by an upper layer.The measurement is an operation which the mobile terminal needs toperform also in order to recognize that the mobile terminal has movedand the base station which the mobile terminal can receive a downlink (adownlink signal or a downlink radio wave) has changed, the best basestation (cell) (providing the highest received power) included in thebase stations from which the mobile terminal can receive the downlinkhas changed. Therefore, unless the mobile terminal does not carry outthe measurement, the mobility (Mobility) management becomes impossiblein the mobile communication system. On the other hand, a base stationwhich constructs an MBSFN synchronization area (MBSFN SynchronizationArea) in an MBMS transmission dedicated frequency layer, and a basestation which constructs a unicast/mixed frequency layer areasynchronous with each other. A problem with the configuration of aconventional mobile communication systems and a conventionalcommunication method is therefore that because a mobile terminalcurrently receiving an MBMS service in an MBMS transmission dedicatedfrequency layer performs a measurement in a unicast/mixed frequencylayer, the reception of the MBMS is interrupted. It is therefore afurther object of the present invention to provide a method of enablinga mobile terminal currently receiving an MBMS service in an MBMStransmission dedicated frequency layer to perform a measurement in aunicast/mixed frequency layer without the reception of the MBMS beinginterrupted, and a mobile communication system which enables the methodto be implemented therein.

Furthermore, nonpatent reference 1 discloses existence of an MBMStransmission dedicated frequency layer, and existence and features of anMBMS dedicated cell. In contrast, nonpatent reference 1 does notdisclose a method of enabling a mobile terminal to move to an MBMStransmission dedicated frequency layer and a method of selecting adesired service. It is another object of the present invention toprovide a method of selecting a desired service in an MBMS transmissiondedicated frequency layer, and a mobile communication system whichenables the method to be implemented therein.

Furthermore, it can be understood from chapter 15 of nonpatent reference1 that an MBSFN area consists of cell groups included in an MBSFNsynchronization area which is adjusted in order to implement MBSFNtransmission. Therefore, there is a case in which MBSFN transmission isnot implemented in a different MBSFN area. Therefore, the followingproblem arises. More specifically, when a mobile terminal currentlyreceiving an MBMS service transmitted via a multi-cell transmissionscheme from MBMS dedicated cells or unicast/MBMS mixed cells in aunicast/mixed frequency layer carries out a handover, the followingproblem arises. Hereafter, a case in which the unicast/MBMS mixed cellwhich is the handover source (the current serving cell), and aunicast/MBMS mixed cell which is the handover destination (a basestation which has been newly selected as the serving cell (a new servingcell: New Serving cell)) do not belong to the same MBSFN area will beconsidered. In this case, there is a possibility that because thehandover source and destination belong to different MBSFN areas, thecontents of receivable MBMS services respectively in the MBSFN areasdiffer from each other. Therefore, there arises a problem that aninterruption of reception of an MBMS service occurs due to a handover.

Means for Solving the Problem

In accordance with the present invention, there is provided acommunication system which uses an OFDM (Orthogonal Frequency DivisionMultiplexing) method as a downlink access method, and also uses anSC-FDMA (Single Career Frequency Division Multiple Access) method as anuplink access method, and which can transmit broadcast type data forproviding an MBMS (Multimedia Broadcast Multicast Service) which is apoint-to-multipoint broadcast communication service to a mobile terminaland can also transmit point-to-point dedicated communication data to amobile terminal, in which the communication system has three types ofcells including a unicast cell to and from which a mobile terminal cantransmit and receive the dedicated communication data, an MBMS dedicatedcell from which the mobile terminal can receive the broadcast type data,but to and from which the mobile terminal cannot transmit and receivethe dedicated communication data, and an MBMS/Unicast-mixed cell whichcan provide both a unicast cell service and an MBMS dedicated cellservice, and, while receiving the broadcast type data transmitted fromthe MBMS dedicated cell, the mobile terminal makes a notification of anMBMS receiving state via the unicast cell or the MBMS/Unicast-mixedcell, and the communication system transmits a paging signal destinedfor the mobile terminal currently receiving the broadcast type datatransmitted from the MBMS dedicated cell on a basis of a tracking area(Tracking Area) in which the mobile terminals is tracked, the trackingarea being determined on a basis of information transmitted from themobile terminal.

In accordance with the present invention, there is provided acommunication system which uses an OFDM (Orthogonal Frequency DivisionMultiplexing) method as a downlink access method, and also uses anSC-FDMA (Single Career Frequency Division Multiple Access) method as anuplink access method, and which can transmit broadcast type data forproviding an MBMS (Multimedia Broadcast Multicast Service) which is apoint-to-multipoint broadcast communication service to a mobile terminaland can also transmit point-to-point dedicated communication data to amobile terminal, in which the communication system has an MBSFN(Multimedia Broadcast multicast service Single Frequency Network)synchronization area comprised of a plurality of MBMS dedicated cellsfrom each of which the mobile terminal can receive the broadcast typedata, but to and from each of which the mobile terminal cannot transmitand receive the dedicated communication data, the plurality of MBMSdedicated cells being synchronized with one another at a singlefrequency, and the MBMS dedicated cell which constructs the MBSFNsynchronization area discontinues transmission of MBMS data to themobile terminal during a certain time period to provide a receptiondiscontinuous time period during which the mobile terminal does notreceive the MBMS data.

Advantages of the Invention

In the communication system in accordance with the present inventionwhich uses the OFDM (Orthogonal Frequency Division Multiplexing) methodas the downlink access method, and also uses the SC-FDMA (Single CareerFrequency Division Multiple Access) method as the uplink access method,and which can transmit broadcast type data for providing an MBMS(Multimedia Broadcast Multicast Service) which is a point-to-multipointbroadcast communication service to a mobile terminal and can alsotransmit point-to-point dedicated communication data to a mobileterminal, the communication system has three types of cells including aunicast cell to and from which a mobile terminal can transmit andreceive dedicated communication data, an MBMS dedicated cell from whicha mobile terminal can receive broadcast type data, but to and from whichthe mobile terminal cannot transmit and receive dedicated communicationdata, and an MBMS/Unicast-mixed cell which can provide both a unicastcell service and an MBMS dedicated cell service, and a mobile terminalcurrently receiving broadcast type data transmitted from the MBMSdedicated cell makes a notification of an MBMS receiving state via theunicast cell or the MBMS/Unicast-mixed cell and the communication systemtransmits a paging signal destined for the mobile terminal currentlyreceiving broadcast type data transmitted from the MBMS dedicated cellon a basis of a tracking area (Tracking Area) in which the mobileterminal is tracked, the tracking area being determined on a basis ofinformation transmitted from the mobile terminal. Therefore, the mobileterminal can specify MBMS data (an MTCH and an MCCH) which the mobileterminal receives or is receiving, and the communication system cantransmit a paging signal to the mobile terminal for which an MBMSservice is provided from the MBMS transmission dedicated cell.

In the communication system in accordance with the present inventionwhich uses the OFDM (Orthogonal Frequency Division Multiplexing) methodas the downlink access method, and also uses the SC-FDMA (Single CareerFrequency Division Multiple Access) method as the uplink access method,and which can transmit broadcast type data for providing an MBMS(Multimedia Broadcast Multicast Service) which is a point-to-multipointbroadcast communication service to a mobile terminal and can alsotransmit point-to-point dedicated communication data to a mobileterminal, the communication system has an MBSFN (Multimedia Broadcastmulticast service Single Frequency Network) synchronization areacomprised of a plurality of MBMS dedicated cells from each of which amobile terminal can receive broadcast type data, but to and from each ofwhich the mobile terminal cannot transmit and receive dedicatedcommunication data, the plurality of MBMS dedicated cells beingsynchronized with one another at a single frequency, and an MBMSdedicated cell which constructs the MBSFN synchronization areadiscontinues transmission of MBMS data to a mobile terminal during acertain time period to provide a reception discontinuous time periodduring which the mobile terminal does not receive the MBMS data.Therefore, the mobile terminal becomes able to carry out a measurementprocess and location registration during this reception discontinuoustime period, and the communication system can transmit a paging signalto the mobile terminal for which an MBMS service is provided from theMBMS transmission dedicated cell.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory drawing showing the configuration of acommunication system which uses an LTE method;

FIG. 2 is an explanatory drawing showing the configuration of a radioframe for use in the communication system which uses an LTE method;

FIG. 3 is an explanatory drawing showing the configuration of an MBSFN(Multimedia Broadcast multicast service Single Frequency Network) frame;

FIG. 4 is an explanatory drawing explaining physical channels for use inthe communication system which uses an LTE method;

FIG. 5 is an explanatory drawing explaining transport channels for usein the communication system which uses an LTE method;

FIG. 6 is an explanatory drawing explaining logical channels for use inthe communication system which uses an LTE method;

FIG. 7 is an explanatory drawing explaining a relation between an MBSFNsynchronization area and MBSFN areas;

FIG. 8 is an explanatory drawing explaining the logical architecture(Logical Architecture) of E-MBMS;

FIG. 9 is an explanatory drawing explaining the architecture(Architecture) of E-MBMS;

FIG. 10 is a block diagram showing the whole configuration of a mobilecommunication system in accordance with the present invention;

FIG. 11 is a block diagram showing the configuration of a mobileterminal;

FIG. 12 is a block diagram showing the configuration of a base station;

FIG. 13 is a block diagram showing the configuration of an MME (MobilityManagement Entity);

FIG. 14 is a block diagram showing the configuration of an MCE(Multi-cell/multicast Coordination Entity);

FIG. 15 is a block diagram showing the configuration of an MBMS gateway;

FIG. 16 is a flow chart showing an outline of processing including froma process of starting using an MBMS to a process of ending the use ofthe MBMS, which is carried out by a mobile terminal in the communicationsystem which uses an LTE method;

FIG. 17 is a flow chart explaining cell selection made by a unicastside;

FIG. 18 is a flow chart showing an MBMS search process;

FIG. 19 is a flow chart showing an MBMS service selection process;

FIG. 20 is a flow chart showing a process of notifying an MBMS sidereceiving state;

FIG. 21 is a flow chart explaining a unicast side measurement process;

FIG. 22 is a flow chart explaining a discontinuous reception process atthe time of MBMS reception;

FIG. 23 is a flow chart showing an MTCH receiving process and an MBMSreception end process;

FIG. 24 is a flow chart showing a unicast side discontinuous receptionprocess and an MBMS reception end process;

FIG. 25 is an explanatory drawing showing a plurality of MBSFN areaswhich construct an MBSFN synchronization area;

FIG. 26 is a conceptual diagram of mapping to a physical channel in theMBSFN synchronization area when time division multiplexing of MBSFNareas is carried out;

FIG. 27 is a conceptual diagram of mapping to a physical channel in theMBSFN synchronization area when code division multiplexing of MBSFNareas is carried out;

FIG. 28 is an explanatory drawing showing a plurality of MBSFN areaswhich construct an MBSFN synchronization area, and also showing an MBSFNarea covering a plurality of MBSFN areas;

FIG. 29 is an explanatory drawing showing mapping to a physical channelin an MBSFN synchronization area in a case in which time divisionmultiplexing of an MBSFN area covering other MBSFN areas and the otherMBSFN areas covered is carried out, and code division multiplexing isused as a multiplexing method of multiplexing the MBSFN areas covered;

FIG. 30 is an explanatory drawing showing a relation between adiscontinuous reception period during which transmission of MBMS data toa mobile terminal is discontinued and the mobile terminal is not doingany receiving operation of receiving MBMS data, and a discontinuousreception cycle in which the discontinuous reception is repeated;

FIG. 31 is an explanatory drawing explaining the details of a trackingarea list;

FIG. 32 is a view of examples of the structure of a channel onto which apaging signal in a frequency layer dedicated to MBMS transmission ismapped;

FIG. 33 is an explanatory drawing showing an example of a method ofmapping a paging signal onto a physical area on a physical multicastchannel (PMCH) onto which the paging signal is to be mapped;

FIG. 34 is an explanatory drawing showing an example of the method ofmapping a paging signal onto a physical area on a physical multicastchannel (PMCH) onto which the paging signal is to be mapped;

FIG. 35 is an explanatory drawing showing mapping to a physical channelin an MBSFN synchronization area in a case in which time divisionmultiplexing of an MBSFN area covering other MBSFN areas and the otherMBSFN areas covered is carried out, and code division multiplexing isused as a multiplexing method of multiplexing the MBSFN areas covered;

FIG. 36 is an explanatory drawing showing a method of mapping apaging-related signal onto a multicast control channel in order todeliver control information to an MBSFN area including a plurality ofMBSFN areas;

FIG. 37 is a flow chart showing a process of measuring the quality of amulticast control channel currently being received;

FIG. 38 is a table showing a concept of the capability of a mobileterminal;

FIG. 39 is an explanatory drawing showing the structure of a physicalmulticast channel disposed for each MBSFN (Multimedia Broadcastmulticast service Single Frequency Network) area;

FIG. 40 is an explanatory drawing showing the structure of a physicalmulticast channel disposed for each MBSFN (Multimedia Broadcastmulticast service Single Frequency Network) area;

FIG. 41 is an explanatory drawing showing the structure of a PMCHdisposed for each MBSFN area;

FIG. 42 is an explanatory drawing showing the structure of a physicalchannel dedicated to paging which is transmitted via a multi-celltransmission scheme in an MBSFN area;

FIG. 43 is an explanatory drawing showing the configuration of an MBSFNsubframe;

FIG. 44 is an explanatory drawing showing a method of mapping a pagingsignal onto a paging dedicated channel (DPCH);

FIG. 45 is an explanatory drawing showing the method of mapping a pagingsignal onto a paging dedicated channel (DPCH);

FIG. 46 is an explanatory drawing showing the structure of a physicalchannel (a main PMCH) which is transmitted via a multi-cell transmissionscheme in an MBSFN synchronization area;

FIG. 47 is an explanatory drawing showing the configuration of a radioframe via which a main PMCH is transmitted;

FIG. 48 is an explanatory drawing showing the configuration of a radioframe via which a main PMCH is transmitted within the same subframe asthat within which a synchronization channel SCH is transmitted;

FIG. 49 is an explanatory drawing showing the structure of a main PMCHin which an area for a paging signal is disposed;

FIG. 50 is an explanatory drawing showing a method of transmitting apaging signal to either an MBSFN area or some cells in an MBSFNsynchronization area;

FIG. 51 is an explanatory drawing showing an example of a code forpadding for each cell which is disposed in a cell which does nottransmit a paging signal;

FIG. 52 is an explanatory drawing showing a method of using a code forpaging transmission cell identification;

FIG. 53 is an explanatory drawing showing a mapping method in a case ofcarrying MBMS-related information and a paging signal onto a multicastcontrol channel (MCCH) as information elements;

FIG. 54 is an explanatory drawing showing a mapping method in a case ofmultiplexing a logical channel PCCH with logical channels MTCH and MCCHto map them onto a transport channel MCH;

FIG. 55 is an explanatory drawing showing a mapping method in a case ofmapping a logical channel PCCH onto a transport channel PCH, carryingout multiplexing of logical channels MTCH and MCCH to map them onto atransport channel MCH, and further multiplexing the PCH and the MCH tomap them onto a physical multicast channel;

FIG. 56 is an explanatory drawing showing a mapping method in a case ofmapping a logical channel PCCH including a paging signal onto atransport channel PCH, carrying out multiplexing of logical channelsMTCH and MCCH to map them on a transport channel MCH, and furthermapping the PCH onto a physical channel dedicated to paging;

FIG. 57 is an explanatory drawing showing a mapping method at the timeof disposing a main PMCH as a physical channel common in an MBSFNsynchronization area;

FIG. 58 is a flow chart showing a unicast side measurement process;

FIG. 59 is a flow chart showing an MTCH receiving process;

FIG. 60 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 61 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 62 is an explanatory drawing showing a relation between adiscontinuous reception period during which transmission of MBMS data toa mobile terminal is discontinued and the mobile terminal is not doingany receiving operation of receiving MBMS data, and a discontinuousreception cycle in which the discontinuous reception is carried out;

FIG. 63 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 64 is a flow chart showing a search method of searching for an MBMSwhich is explained in Embodiment 12;

FIG. 65 is an explanatory drawing showing the configuration of a mainPMCH in an MBSFN synchronization area;

FIG. 66 is an explanatory drawing showing the configuration of a mainPMCH in an MBSFN synchronization area;

FIG. 67 is a flow chart showing the search method of searching for anMBMS which is explained in Embodiment 12;

FIG. 68 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 69 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 70 is an explanatory drawing showing the configuration of a PMCHfor each MBSFN area;

FIG. 71 is an explanatory drawing showing an example of discontinuousreception information;

FIG. 72 is an explanatory drawing showing an example of discontinuousreception information;

FIG. 73 is an explanatory drawing showing a problem of the presentinvention;

FIG. 74 is a sequence diagram in a case of deriving a paging occasiononto which a notification of allocation information about MBSFNsubframes and a paging signal are mapped;

FIG. 75 is a view explaining the configuration of MBSFN subframes foreach MBSFN area in each cell in a case in which a DRX period is alsotaken into consideration;

FIG. 76 is a flow chart explaining a discontinuous reception preparationprocess at the time of MBMS reception in Embodiment 15;

FIG. 77 is a flow chart explaining a discontinuous reception process atthe time of MBMS reception in Embodiment 15;

FIG. 78 is a view explaining the details of a tracking area list inEmbodiment 16;

FIG. 79 is a view explaining the details of a tracking area list inEmbodiment 16;

FIG. 80 is a view explaining an arbitrary MBMS dedicated cell in oneMBSFN area being determined as a tracking area;

FIG. 81 is a view explaining the details of a tracking area list inEmbodiment 17.

FIG. 82 is a view explaining a tracking area being constructed by anarbitrary MBMS dedicated cell in a plurality of MBSFN areas;

FIG. 83 is a flow chart showing broadcasting regarding a receivableMBMS, an MBMS search, and an MBMS service selecting process;

FIG. 84 is a table explaining a correspondence between service numbersand service contents;

FIG. 85 is a flow chart showing broadcasting regarding a receivableMBMS, an MBMS search, and an MBMS service selecting process;

FIG. 86 is a flow chart showing a process, which is carried out by amobile terminal currently receiving an MBMS service which is transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells, ofcarrying out a handover;

FIG. 87 is a flow chart showing a process, which is carried out by amobile terminal currently receiving an MBMS service which is transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells, ofcarrying out a handover;

FIG. 88 is a flow chart showing a process, which is carried out by amobile terminal currently receiving an MBMS service which is transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells, ofcarrying out a handover;

FIG. 89 is a flow chart showing a process, which is carried out by amobile terminal currently receiving an MBMS service which is transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells, ofcarrying out a handover;

FIG. 90 is a flow chart showing a process, which is carried out by amobile terminal currently receiving an MBMS service which is transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells, ofcarrying out a handover;

FIG. 91 is an explanatory drawing showing a concept regardingmultiplexing of MBSFN subframes in an MBSFN area;

FIG. 93 is an explanatory drawing explaining a problem of the presentinvention;

FIG. 93 is a sequence diagram in a case of determining subframes in aradio frame for paging occasion onto which a paging signal is mapped;

FIG. 94 is a sequence diagram in a case of determining subframes in aradio frame for paging occasion onto which a paging signal is mapped;

FIG. 95 is a table showing a correspondence between subframes in a radioframe for paging occasion, and the number of subframes excludingsubframes which can be MBSFN subframes;

FIG. 96 is a table showing a correspondence between subframes in a radioframe for paging occasion, and MBSFN subframe numbers;

FIG. 97 is a sequence diagram in a case of determining subframes in aradio frame for paging occasion, which is used in variant 5 ofEmbodiment 23;

FIG. 98 is a view explaining a case in which two TAs(MBMS) (TA(MBMS) #1and TA(MBMS) #2) are formed in one MBSFN area;

FIG. 99 is a view showing that TDM of a paging signal is carried out foreach TA(MBMS), and the paging signal is mapped;

FIG. 100 is a view explaining a structure in which a paging signaldedicated channel and a PMCH are disposed in an identical MBSFNsubframe;

FIG. 101 is a view explaining a method of mapping paging informationonto a physical area of each physical channel;

FIG. 102 is a view explaining a system bandwidth of each cell in anMBSFN area; and

FIG. 103 is a view explaining a method of broadcasting a systembandwidth from each cell to mobile terminals being served by the cell.

EXPLANATIONS OF REFERENCE CHARACTERS

-   101 Mobile terminal, 102 Base station, 103 MME (Mobility Management    Entity), 104 S-GW (Serving Gateway).

PREFERRED EMBODIMENTS OF THE INVENTION Embodiment 1

FIG. 10 is a block diagram showing the whole configuration of a mobilecommunication system in accordance with the present invention. In FIG.10, a mobile terminal 101 carries out transmission and reception ofcontrol data (C-plane) and user data (U-plane) to and from a basestation 102. Base stations 102 are classified into unicast cells 102-1each of which handles only transmission and reception of unicast, mixedcells 102-2 each of which handles transmission and reception of unicastand MBMS services (MTCH and MCCH), and MBMS dedicated cells 102-3 eachof which handles only transmission and reception of MBMS services. Eachof a unicast cell 102-1 handling transmission and reception of unicastand an MBMS/Unicast-mixed cell (a mixed cell) 102-2 handlingtransmission and reception of unicast is connected to an MME 103 via aninterface S1_MME. Each of a unicast cell 102-1 handling transmission andreception of unicast and a mixed cell 102-2 handling transmission andreception of unicast is also connected to an S-GW 104 via an interfaceS1 U for transmission and reception of unicast user data. The MME 103 isconnected to a PDNGW (Packet Data Network Gateway) 902 via an interfaceS11. An MCE 801 allocates radio resources to all base stations 102existing in an MBSFN area in order to carry out multi-cell (MC)transmission. For example, a case in which both an MBSFN area #1consisting of one or more MBMS/Unicast-mixed cells 102-2, and an MBSFNarea #2 consisting of one or more MBMS dedicated cells 102-3 exist willbe considered. An MBMS/Unicast-mixed cell 102-2 is connected to an MCE801-1 that allocates radio resources for all the base stations existingin the MBSFN area #1 via an interface M2. Furthermore, an MBMS dedicatedcell 102-3 is connected to an MCE 801-2 that allocates radio resourcesfor all the base stations existing in the MBSFN area #2 via an interfaceM2.

An MBMS GW 802 can be divided into an MBMS CP 802-1 that handles controldata, and an MBMS UP 802-2 that handles user data. Each of anMBMS/Unicast-mixed cell 102-2 and an MBMS dedicated cell 102-3 isconnected to the MBMS CP 802-1 via an interface M1 for transmission andreception of MBMS-related control data. Each of an MBMS/Unicast-mixedcell 102-2 and an MBMS dedicated cell 102-3 is connected to the MBMS UP802-2 via an interface M1_U for transmission and reception ofMBMS-related user data. The MCE 801 is connected to the MBMS CP 802-1via an interface M3 for transmission and reception of MBMS-relatedcontrol data. The MBMS UP 802-2 is connected to an eBMSC 901 via aninterface SGimb. The MBMS GW 802 is connected to the eBMSC 901 via aninterface SGmb. The eBMSC 901 is connected to a content provider. TheeBMSC 901 is connected to a PDNGW 902 via an interface SGi. The MCE 801is connected to an MME 103 via an interface (IF) between MME and MCEwhich is a new interface.

FIG. 11 is a block diagram showing the configuration of a mobileterminal 101 for use in the system in accordance with the presentinvention. In FIG. 11, a transmitting process of the mobile terminal 101is performed as follows. First, control data from a protocol processingunit 1101 and user data from an application unit 1102 are stored in atransmission data buffer unit 1103. The data stored in the transmissiondata buffer unit 1103 are delivered to an encoder unit 1104, and aresubjected to an encoding process such as an error correction. There canexist data which are outputted directly from the transmission databuffer unit 1103 to a modulating unit 1105 without being encoded. Amodulation process is performed on the data on which the encodingprocess has been performed by the encoder unit 1104 by the modulatingunit 1105. After the modulated data are converted into a basebandsignal, the baseband signal is outputted to a frequency converting unit1106 and is converted into a transmission signal having a radiotransmission frequency by the frequency converting unit 1106. Afterthat, the transmission signal is transmitted to a base station 102 viaan antenna 1107. The mobile terminal 101 also performs a receivingprocess as follows. A radio signal from abase station 102 is received bythe antenna 1107. The received signal having a radio reception frequencyis converted into a baseband signal by the frequency converting unit1106, and a demodulation process is performed on the baseband signal bya demodulating unit 1108. Data which are obtained through thedemodulating process are delivered to a decoder unit 1109, and aresubjected to a decoding process such as an error correction. Controldata included in the decoded data are delivered to the protocolprocessing unit 1101 while user data included in the decoded data aredelivered to the application unit 1102. The series of processes carriedout by the mobile terminal are controlled by a control unit 1110.Therefore, although not shown in the drawing, the control unit 1110 isconnected to each of the units (1101 to 1109).

FIG. 12 is a block diagram showing the configuration of a base station102. The base station 102 performs a transmitting process as follows. AnEPC communication unit 1201 transmits and receives data between the basestation 102 and an EPC (an MME 103 and an S-GW 104). An other basestation communicating unit 1202 transmits and receives data to and fromanother base station. Each of the EPC communication unit 1201 and theother base station communicating unit 1202 carries out reception andtransmission of information from and to a protocol processing unit 1203.Control data from the protocol processing unit 1203, and user data andcontrol data from the EPC communication unit 1201 and the other basestation communicating unit 1202 are stored in a transmission data bufferunit 1204. The data stored in the transmission data buffer unit 1204 aredelivered to an encoder unit 1205, and subjected to an encoding processsuch as an error correction. There can exist data which are outputteddirectly from the transmission data buffer unit 1204 to a modulatingunit 1206 without being encoded. The modulating unit 1206 performs amodulation process on the encoded data. After the modulated data areconverted into a baseband signal, the baseband signal is outputted to afrequency converting unit 1207 and is converted into a transmissionsignal having a radio transmission frequency by the frequency convertingunit 1207. After that, the transmission signal is transmitted from anantenna 1208 to one or more mobile terminals 101. The base station 102also performs a receiving process as follows. A radio signal from one ormore mobile terminals 101 is received by the antenna 1208. The receivedsignal having a radio reception frequency is converted into a basebandsignal by the frequency converting unit 1207, and a demodulation processis performed on the baseband signal by a demodulating unit 1209. Datawhich are obtained through the demodulating process are delivered to adecoder unit 1210, and are subjected to a decoding process such as anerror correction. Control data among the decoded data are delivered tothe protocol processing unit 1203 or the EPC communication unit 1201 andthe other base station communicating unit 1202, and user data among thedecoded data are delivered to the EPC communication unit 1201 and theother base station communicating unit 1202. The series of processescarried out by the base station 102 are controlled by a control unit1211. Therefore, although not shown in the drawing, the control unit1211 is connected to each of the units (1201 to 1210).

FIG. 13 is a block diagram showing the configuration of an MME (MobilityManagement Entity). A PDN GW communication unit 1301 carries outtransmission and reception of data between the MME 103 and a PDN GW 902.A base station communication unit 1302 carries out transmission andreception of data between the MME 103 and a base station 102 via anS1_MME interface. When data received from the PDN GW 902 is user data,the user data is delivered from the PDN GW communication unit 1301 tothe base station communication unit 1302 via a user plane processingunit 1303, and is then transmitted to one or more base stations 102.When data received from a base station 102 is user data, the user datais delivered from the base station communication unit 1302 to the PDN GWcommunication unit 1301 via the user plane processing unit 1303, and isthen transmitted to the PDN GW 902.

An MCE communication unit 1304 carries out transmission and reception ofdata between the MME 103 and an MCE 801 via an IF between MME and MCE.When data received from the PDN GW 902 is control data, the control datais delivered from the PDN GW communication unit 1301 to a control planecontrol unit 1305. When data received from a base station 102 is controldata, the control data is delivered from the base station communicationunit 1302 to the control plane control unit 1305. Control data receivedfrom an MCE 801 is delivered from the MCE communication unit 1304 to thecontrol plane control unit 1305. The results of a process carried out bythe control plane control unit 1305 are transmitted to the PDN GW 902via the PDN GW communication unit 1301, are then transmitted, via anS1_MME interface, to one or more base stations 102 by way of the basestation communication unit 1302, and are then transmitted, via an IFbetween MME and MCE, to one or more MCEs 801 by way of the MCEcommunication unit 1304. A NAS security unit 1305-1, an SAE bearercontrol unit 1305-2, and an idle state (Idle State) mobility managingunit 1305-3 are included in the control plane control unit 1305, and thecontrol plane control unit carries out general processes for controlplane. The NAS security unit 1305-1 carries out security work for a NAS(Non-Access Stratum) message, etc. The SAE bearer control unit 1305-2carries out management of a bearer of SAE (System ArchitectureEvolution), etc. The idle state mobility managing unit 1305-3 carriesout mobility management of an idle state (an LTE-IDLE state, simplyreferred to as idle), generation and control of a paging signal at thetime of an idle state, addition, deletion, update, and retrieval of atracking area (TA) of one or more mobile terminals 101 being served by abase station, management of a tracking area list (TA List), etc. The MMEstarts a paging protocol by transmitting paging messages to cellsbelonging to a tracking area (TA) in which UEs are registered. Theseries of processes carried out by the MME 103 are controlled by acontrol unit 1306. Therefore, although not shown in the drawing, thecontrol unit 1306 is connected to each of the units (1301 to 1305).

FIG. 14 is a block diagram showing the configuration of an MCE(Multi-cell/multicast Coordination Entity). An MBMS GW communicationunit 1401 carries out transmission and reception of control data betweenthe MCE 801 and an MBMS GW 802 via an M3 interface. A base stationcommunication unit 1402 carries out transmission and reception ofcontrol data between the MCE 801 and a base station 102 via an M2interface. An MME communication unit 1403 carries out transmission andreception of control data between the MCE 801 and an MME 103 via an IFbetween MME and MCE. An MC transmission scheduler unit 1404 carries outscheduling of multi-cell transmission of one or more MBSFN areas whichthe MC transmission scheduler unit manages by using control data fromthe MBMS GW 802 delivered thereto via the MBMS GW communication unit1401, control data from a base station 102 in an MBSFN (MultimediaBroadcast multicast service Single Frequency Network) area, which aredelivered thereto via the base station communication unit 1402, andcontrol data from the MME 103 which are delivered thereto via the MMEcommunication unit 1403. As an example of the scheduling, radioresources (time, frequency, etc.) of a base station, a radioconfiguration (a modulation method, a code, etc.), etc. can be provided.The results of the scheduling of multi-cell transmission are deliveredto the base station communication unit 1402, and are then transmitted toone or more base stations 102 in the MBSFN area. The series of processescarried out by the MCE 801 are controlled by a control unit 1405.Therefore, although not shown in the drawing, the control unit 1405 isconnected to each of the units (1401 to 1404).

FIG. 15 is a block diagram showing the configuration of an MBMS gateway.In FIG. 15, an eBMSC communication unit 1501 of the MBMS GW 802 carriesout transmission and reception of data (user data and control data)between the MBMS GW 802 and an eBMSC 901. The MCE communication unit1502 carries out transmission and reception of control data between theMBMS GW 802 and an MCE 801 via an M3 interface. Control data receivedfrom the eBMSC 901 are delivered to an MBMS CP unit 1503 via the eBMSCcommunication unit 1501, and, after being processed by the MBMS CP unit1503, are transmitted to one or more MCEs 801 via the MCE communicationunit 1502. Control data received from the MCE 801 are delivered to theMBMS CP unit 1503 via the MCE communication unit 1502, and after beingprocessed by the MBMS CP unit 1503, are transmitted to the eBMSC901and/or the MCE 801 via the eBMSC communication unit 1501. A base stationcommunication unit 1504 transmits user data (also referred to as trafficdata) to the MBMS GW 802 and one or more base stations via an M1_Uinterface. User data received from the eBMSC 901 are delivered to anMBMS UP unit 1505 via the eBMSC communication unit 1501, and, afterbeing processed by the MBMS UP unit 1505, are transmitted to one or morebase stations 102 via the base station communication unit 1504. The MBMSCP unit 1503 and the MBMS UP unit 1505 are connected to each other. Theseries of processes carried out by the MBMS GW 802 is controlled by acontrol unit 1506. Therefore, although not shown in the drawing, thecontrol unit 1506 is connected to each of the units (1501 to 1506).

Next, an example of a flow of processing carried out by the mobilecommunication system in accordance with the present invention will beshown in FIG. 16. FIG. 16 is a flow chart showing an outline ofprocessing including from a process of starting using an MBMS to aprocess of ending the use of the MBMS, which is carried out by a mobileterminal in the communication system which uses an LTE method. Themobile terminal, in step ST1601 of FIG. 16, carries out a cell selectionof a serving cell in an MBMS/Unicast-mixed cell. Hereafter, the processof step 1601 will be referred to as a “unicast side cell selection”. Anetwork side, in step ST1601-1, carries out a process of “broadcastinginformation about a receivable MBMS” to the mobile terminal. Morespecifically, the network side informs the mobile terminal that acurrently-available MBMS service exists, or about information regardingfrequencies of the MBMS service (a list of frequencies). Because throughthe process of step ST1601-1, the mobile terminal can know that acurrently-available MBMS service exists, or know the information aboutfrequencies of the MBMS service, the mobile terminal does not have tosearch for a receivable frequency in a round-robin manner. As a result,there is provided an advantage of shortening a control delay timeoccurring before the mobile terminal receives a service at a frequencyother than a currently-selected frequency.

The mobile terminal, in step ST1602, carries out a search process ofsearching for an MBMS transmission dedicated cell on the basis of theinformation transmitted thereto from the network side in step ST1601. Asan example of the search process, there is provided acquisition oftiming synchronization (synchronization with radio frame timing), andsystem information, such as a system bandwidth, the number oftransmission antennas, an MBSFN area identifier (ID) (also referred toas an MBSFN area number), and MCCH (multicast control channel)-relatedinformation, etc. Hereafter, the process of step 1602 will be referredto as a “search for MBMS”. The mobile terminal, in step ST1603, receivesinformation used for receiving an MBMS service (MCCH and MTCH) in theMBMS transmission dedicated cell from the network side. Hereafter, theprocess of step 1603 will be referred to as “MBMS area informationacquisition”. The user (mobile terminal), in step ST1604, selects anMBMS service which the user desires by using the information used forreceiving the MBMS service received from the network side in stepST1603. Hereafter, the process of step 1604 will be referred to as “MBMSservice selection”.

As previously explained as the problems, it has been examined that in acommunication system based on an LTE method, only a downlink fortransmitting broadcast data provided by an MBMS service to mobileterminals is disposed while any uplinks are omitted, and a celldedicated to MBMS transmission which implements a simple systemconfiguration is disposed. In the above-mentioned explanation of stepsST1601-1 to ST1604, the method of selecting an MBMS service using suchan MBMS transmission dedicated cell is disclosed. Therefore, there isprovided an advantage of enabling the mobile terminal to receive adesired MBMS service by means of the MBMS transmission dedicated cellthrough the previously-explained series of processes.

The mobile terminal, in step ST1605, makes preparations for carrying outdiscontinuous reception of MBMS data from the MBMS transmissiondedicated cell by using the information used for receiving an MBMSservice received from the network side in step ST1603. Hereafter, theprocess of step 1605 will be referred to as “preparations fordiscontinuous reception at the time of MBMS reception”. The mobileterminal, in step ST1606, carries out an “MBMS side receiving statenotification” process of notifying the state of receiving the MBMS inthe MBMS transmission dedicated cell to the network side. Because theMBMS transmission dedicated cell does not have any uplink disposedtherein, any mobile terminal currently receiving MBMS data in the MBMSdedicated cell cannot carry out location registration into the networkside. In this case, because the network side cannot specify the cell inwhich the mobile terminal is being located, it is difficult for thenetwork side to transmit a paging signal to the mobile terminal when anincoming call destined for the mobile terminal in question is occurring.Because the network side, in this step ST1606, can know that the mobileterminal in question is receiving an MBMS service in the MBMStransmission dedicated cell, and becomes able to keep track of themobile terminal, when an incoming call destined for the mobile terminalcurrently using the MBMS service in the MBMS transmission dedicated cellis occurring, the network side can transfer paging information to theMBMS transmission dedicated cell via an MME 103 and an MCE 801-1 tonotify that a dedicated incoming call destined for the mobile terminalcurrently using the MBMS service is occurring. Therefore, the problemabout paging to a mobile terminal currently using an MBMS service in anMBMS transmission dedicated cell can be solved.

The mobile terminal, in step ST1607, carries out a measurement(measurement) process including a measurement of the electric fieldintensity of a unicast cell (102-1 in FIG. 10) and/or that of anMBMS/Unicast-mixed cell (102-2 in FIG. 10), and a cell selection. Thisprocess will be referred to as a “unicast side measurement”. Byperforming step ST1607, even if the mobile terminal is receiving MBMSdata in the MBMS transmission dedicated cell, the mobile terminalbecomes able to carryout a process including a measurement of a unicastcell (102-1 in FIG. 10) and a measurement of an MBMS/Unicast-mixed cell(102-2 in FIG. 10), a cell selection, location registration, etc.Because the mobile terminal currently using the MBMS service in the MBMStransmission dedicated cell has selected and updated either the unicastcell or the MBMS/Unicast-mixed cell which is the target for transmissionby carrying out this measurement process, there is provided an advantageof being able to ensure mobility in the MBMS dedicated cells in whichany uplink does not exist. Therefore, the mobile terminal currentlyusing the MBMS service in the MBMS dedicated cell becomes able to surelycarry out a process regarding mobility, such as location registration,via, for example, the unicast cell or the MBMS/Unicast-mixed cell, and,as a result, the network side becomes able to send a paging signal tothe mobile terminal currently using the MBMS service in the MBMStransmission dedicated cell. The mobile terminal in question alsocarries out downlink synchronization establishment with a unicast/mixedfrequency layer through a measurement at measurement periods (cycles).Accordingly, even in a case in which in an MBMS transmission dedicatedcell in which any uplink does not exist, a mobile terminal transmits aresponse to a paging signal via an MBMS/Unicast-mixed cell, which is achallenge of the present invention, the control delay time can bereduced.

The mobile terminal, in step ST1608, carries out discontinuous receptionin order to receive paging signals. More concretely, when a dedicatedincoming call destined for the mobile terminal in question is occurring,the network side transmits a paging signal, via a downlink of the MBMStransmission dedicated cell, to the mobile terminal currently receivingthe MBMS service from a frequency layer dedicated to MBMS transmissionconsisting of the MBMS transmission dedicated cell. In steps ST1605 toST1608, a notification of paging to the mobile terminal using the MBMSservice in the MBMS transmission dedicated cell, which is a challenge ofthe present invention, can be provided.

The mobile terminal which has not received the paging signal through the“discontinuous reception at the time of MBMS reception” of step ST1608,in step ST1609, receives MBMS traffic data transmitted thereto from theMBMS transmission dedicated cell via a multicasting traffic channel(MTCH). Hereafter, the process of step ST1609 will be referred to as“MTCH reception”. The mobile terminal which is carrying out the “MTCHreception” makes a transition to step ST1607 at the time of the “unicastside measurement”. As an alternative, the mobile terminal which iscarrying out the “MTCH reception” makes a transition to step ST1602,ST1604, or ST1612 when the receive sensitivity becomes worse. Incontrast, the mobile terminal which has received a paging signal throughthe “discontinuous reception at the time of MBMS reception” of stepST1608, in step ST1610, switches from a frequency (f(MBMS)) in thefrequency layer dedicated to MBMS transmission to a frequency(f(Unicast)) in the unicast/mixed frequency layer, and carries outtransmission and reception of control data. Hereafter, the process ofstep ST1610 will be referred to as “unicast side discontinuousreception”. As a result, the mobile terminal in question becomes able totransmit uplink data, such as a response to the paging signal, to thenetwork side via either the unicast cell or the mixed cell. The mobileterminal, in steps ST1611 and ST1612, informs the network side that themobile terminal will end the reception of the MBMS data in the frequencylayer dedicated to MBMS transmission (the MBMS transmission dedicatedcell). By performing step ST1611, the mobile terminal enables thenetwork side to know that the mobile terminal in question will end theuse of the MBMS service. Because what is necessary is just to transmit apaging signal to the mobile terminal which has ended the use of the MBMSservice with the frequency layer dedicated to MBMS transmission viaeither the unicast cell or the mixed cell, the network side can stop theprocess of transmitting the paging signal via the downlink of the MBMStransmission cell. Therefore, effective use of the radio resources ofthe MBMS transmission dedicated cell can be made.

Embodiment 2

In this embodiment, a detailed example of a flow of the processingcarried out by the mobile communication system described in Embodiment 1will be explained with reference to FIG. 17. FIG. 17 is a flow chartexplaining a cell selection on a side of unicast. Each of a unicast celland an MBMS/Unicast-mixed cell (simply refers to a mixed cell (Mixedcell)), in step ST1701, broadcasts a primary synchronization channel(Primary Synchronization Channel: P-SCH) and a secondary synchronizationchannel (Secondary Synchronization Channel: S-SCH), and a referencesignal (also referred to as a reference symbol, Reference Symbol: RS) tomobile terminals being served thereby. Each of the mobile terminals, instep ST1702, receives the P-SCH, the S-SCH, and the RS from the basestation (the unicast cell or/and the mixed cell). Each of the mobileterminals, in step ST1703, carries out an initial cell searchingoperation by using the P-SCH, the S-SCH, and the RS received thereby.The details of the cell searching operation which have been beingdebated in the 3GPP will be explained. In a first step, each of themobile terminals carries out blind detection of the primarysynchronization channel (P-SCH) for which three types of prescribedsequences exist in the mobile communication system. The P-SCH is mappedonto central 72 subcarriers of the system bandwidth in frequency, and ismapped onto the 1st (#0) and 6th (#5) subframes of each radio frame intime. Therefore, each of the mobile terminals which has blind-detectedthe P-SCH can detect 5 ms-timing and know cell groups (first to thirdgroups corresponding to the above-mentioned three types of sequences ofP-SCH). In a second step, each of the mobile terminals carries out blinddetection of the secondary synchronization channel (S-SCH). The mappingpositions of the S-SCH are the same as those of the P-SCH. Each of themobile terminals which has blind-detected the S-SCH can detect 10ms-timing frame synchronization) and know the cell identifier (Cell ID).

Each of the mobile terminals, in step ST1704, carries out a cellselection. The cell selection is a process of selecting one base stationwhich satisfies the requirements for becoming a serving base station(cell) by using the results of a measurement of the downlink receivesensitivity of each of a plurality of base stations, which is carriedout by each of the mobile terminals. As an example of the requirementsfor becoming a serving base station, there can be considered a case inwhich the base station to be selected has the best one of the downlinkreceive sensitivities of the plurality of base stations, or a case inwhich the base station to be selected has a receive sensitivityexceeding a minimum threshold of the receive sensitivity of a servingbase station. As a value which each of the mobile terminals actuallymeasures, there is reference symbol received power (Reference Symbolreceived power: RSRP), or an E-UTRA carrier received signal strengthindicator (E-UTRA carrier received signal strength indicator: RSSI). Aserving base station is a base station which takes charge of schedulingof the mobile terminal in question. Even a base station other than theserving base station for the mobile terminal in question can become aserving base station for other mobile terminals. That is, each of allbase stations each of which is a unicast cell or an MBMS/Unicast-mixedcell has a scheduling function, and can become a serving base stationfor some mobile terminals. Each of the unicast cell and theMBMS/Unicast-mixed cell, in step ST1705, transmits broadcast informationby using a broadcast control channel (BCCH) which is one of the logicalchannels. The broadcast information includes, as an example, ameasurement period length, a discontinuous reception cycle length, andtracking area information (TA information). The measurement periodlength is informed from the network side to the mobile terminals beingserved thereby, and each of the mobile terminals measures a fieldintensity and so on at periods (cycles) of this period length. Thediscontinuous reception cycle length is the length of each of periods atwhich each of the mobile terminals monitors a paging signal periodicallyin order to receive a paging signal in an idle state (Idle State). TheTA information is the information about a “tracking area” (TrackingArea). By sending a paging message to each eNB belonging to the trackingarea in which UEs are registered, an MME starts a paging process (seeTS36.300 19.2.2.1). Each of the mobile terminals, in step ST1706,receives the measurement period length, the discontinuous receptioncycle length, the TA information, etc., via the BCCH, from the servingbase station.

Each unicast cell or each MBMS/Unicast-mixed cell, in step ST1707,broadcasts one or more frequencies of an available MBMS service, i.e.,one or more frequencies of a receivable MBSFN synchronization area(MBSFN Synchronization Area) (referred to as one or more frequenciesf(MBMS)s) to the mobile terminals by using the BCCH. In a W-CDMAcommunication system, a parameter called preferred frequency information(Preferred frequency information: PL information) exists. The PLinformation is mapped onto a multicast control channel (MCCH), which isa logical channel, in the network side, and is broadcasted to the mobileterminals being served by the base station. A problem is, however, thatin an LTE system, a unicast cell which does not provide any MBMS serviceis planned to be disposed, and this unicast cell cannot use the methodof broadcasting a frequency f(MBMS) by using the MCCH which is a channelfor MBMS.

Each of the mobile terminals, in step ST1708, receives the frequencyf(MBMS) transmitted thereto by using the BCCH from the serving basestation. By receiving the frequency f(MBMS), each of the mobileterminals does not have to search for a frequency at which a service canbe provided therefor, other than a currently-selected frequency, in around-robin manner. As a result, there is provided an advantage ofshortening the control delay required for each of the mobile terminalsto receive a service at a frequency other than the currently-selectedfrequency. Steps ST1707 and ST1708 are a detailed example of the“broadcasting information about a receivable MBMS” described inEmbodiment 1. In this case, if each frequency f(MBMS) is determinedstatically (Static) or semi-statically (Semi-Static) in the mobilecommunication system, there can be provided an advantage of shorteningthe control delay time occurring before each of the above-mentionedmobile terminals receives a service at a frequency other than thecurrently-selected frequency without broadcasting each frequency f(MBMS)from the base station. In addition, because it becomes unnecessary tobroadcast each frequency f(MBMS), an advantage of making effective useof the radio resources can also be provided.

As an alternative, the base station, in steps ST1707 and ST1708, canalso broadcast the system bandwidth and the number of transmissionantennas in each frequency f(MBMS) by using the BCCH in addition to eachfrequency f(MBMS). As a result, each of the mobile terminals does nothave to acquire the system information (the system bandwidth and thenumber of transmission antennas) in the frequency layer dedicated toMBMS transmission by receiving frequency f(MBMS) transmitted by usingthe BCCH from the serving base station, in step ST1708. Therefore, therecan be provided an advantage of shortening the control delay time. Thisis because even if the amount of information (the system bandwidth andthe number of transmission antennas) increases, the length of processingtime required for each of the mobile terminals to perform the processingdoes not increase so much because each of the mobile terminals needs toreceive the BCCH from the serving base station in the unicast/frequencylayer in order to receive each frequency f(MBMS), while because each ofthe mobile terminals needs to receive the BCCH in the frequency layerdedicated to MBMS transmission in order to acquire the systeminformation of the frequency layer dedicated to MBMS transmission afterswitching to the frequency layer dedicated to MBMS transmission, andeach of the mobile terminals therefore requires a decoding process ofdecoding another channel newly, a control delay time occurs.

Each of the mobile terminals, in step ST1709, checks to see whether ornot the TA information of the serving base station received in stepST1706 is included in the current tracking area list (TA List) whicheach of the mobile terminals stores in the protocol processing unit 1101or the control unit 1110 thereof. When the TA information is included inthe current tracking area list, each of the mobile terminals makes atransition to step ST1720 of FIG. 18. In contrast, when the TAinformation is not included in the current tracking area list, each ofthe mobile terminals performs step ST1710. Each of the mobile terminals,in step ST1710, transmits an “attach request” (Attach Request) to theserving base station to inform that the TA information is not includedin the current tracking area list. As information included in the“attach request”, there are an identifier (IMSI (International MobileSubscriber Identity)) or S-TMSI (S-Temporary Mobile Subscriber Identity,S-TMSI may be simply referred to as Temporary Mobile Subscriber Identity(TMSI)) of each of the mobile terminals, and the capability (Capability)of each of the mobile terminals. The serving base station which hasreceived the “attach request” in step ST1711, in step ST1712, transmitsthe “attach request” to an MME (Mobility Management Entity) or an HSS(Home Subscriber Server). The MME, in step ST1713, receives the “attachrequest”. The idle state mobility managing unit 1305-3 of the MMEmanages the tracking area list of each of the mobile terminals. The MME,in step ST1714, checks whether or not the serving base station of themobile terminal in question is included in the tracking area list whichis managed by the mobile terminal in question. When the serving basestation of the mobile terminal in question is included in the trackingarea list, the MME makes a transition to step ST1716 of FIG. 18. Whenthe serving base station of the mobile terminal in question is notincluded in the tracking area list, the MME performs step ST1715. Theidle state mobility managing unit 1305-3 of the MME, in step 1715,carries out a process of adding the TA information of the serving basestation of the mobile terminal in question to the tracking area listwhich is managed by the mobile terminal in question (or updating thetracking area list). The MME, in step ST1716, informs an “attach accept”(Attach Accept) to the serving base station. The “attach accept”includes information such as the tracking area list, and an identifier(S-TMSI or the like) which is provided to the mobile terminal. Theserving base station which, in step ST1717, has received the “attachaccept”, in step ST1718, informs the “attach accept” to the mobileterminal in question. The mobile terminal, in step ST1719, receives the“attach accept”.

FIG. 18 is a flow chart showing an MBMS search process. Steps 1720 to1725 of FIG. 18 are a concrete example of the “search for MBMS”described in Embodiment 1. Each of the mobile terminals, in step ST1720,checks to see whether it has received an frequency of a receivable MBSFNsynchronization area (or a frequency of the frequency layer dedicated toMBMS transmission) in step ST1708. That is, each of the mobile terminalschecks to see whether it has received one or more frequencies f(MBMS)s.When there exists no frequency (no f(MBMS)), each of the mobileterminals ends the process. When there exists one or more frequencies(there exists one or more frequencies f(MBMS)s), each of the mobileterminals performs step ST1721. Each of the mobile terminals, in stepST1721, checks to see whether the user has an intention of receiving anMBMS service at a frequency f(MBMS). As an example of the checking, whenthe user has an intention of receiving an MBMS service, he or she uses auser interface to send a command to his or her mobile terminal, and eachof the mobile terminals stores information showing the user's intentionin the protocol processing unit 1101. Each of the mobile terminals, instep ST1721, checks to see whether or not the information showing theuser's intention of receiving an MBMS service is stored in the protocolprocessing unit 1101. When the information showing the user's intentionof receiving an MBMS service is not stored, each of the mobile terminalsrepeats the process of step ST1721. As a method of repeating theprocess, each of the mobile terminals uses a method of carrying out thedetermination of step ST1721 at constant periods (cycles), or a methodof carrying out step ST1721 or ST1720 when receiving a notificationshowing a change in the user's intention of receiving an MBMS servicefrom the user by way of the user interface. In contrast, when theinformation showing the user's intention of receiving an MBMS service isstored, each of the mobile terminals makes a transition to step ST1722.Each of the mobile terminals, in step ST1722, changes the frequency setto the frequency converting unit 1107 (synthesizer) thereof and changesits center frequency to the frequency f(MBMS) to start the searchingoperation of searching for an MBMS. Changing the frequency set to thefrequency converting unit 1107 to change its center frequency isreferred to as re-tune (re-tune). The MBMS dedicated cell, in stepST1723, broadcasts a primary synchronization channel (PrimarySynchronization Signal: P-SCH) and a secondary synchronization channel(Secondary Synchronization Signal: S-SCH), a reference signal (RS(MBMS)), and a BCCH to the mobile terminals being served thereby. Eachof the mobile terminals, in step ST1724, receives the P-SCH, the S-SCH,the RS (MBMS), and the BCCH (broadcast control channel) from the MBMSdedicated cell.

Each of the mobile terminals, in step ST1725, performs the searchingoperation of searching for an MBMS. At that time, each of the mobileterminals measures the reception quality using the reference signal(RS). The searching operation in the frequency layer dedicated to MBMStransmission which has been debated in the 3GPP will be explained. Asequence exclusively used in the frequency layer dedicated to MBMStransmission is added to the P-SCH. It is assumed that the additionalsequence for exclusive use is defined statically. In a first step, eachof the mobile terminals carries out blind detection of the P-SCH in theadditional sequence for exclusive use. The P-SCH is mapped onto central72 subcarriers of the system bandwidth in frequency, and is mapped ontothe 1st (#0) and 6th (#5) subframes of each radio frame in time.Therefore, each of the mobile terminals which has blind-detected theP-SCH can carry out 5 ms-timing detection. Furthermore, the P-SCH istransmitted via a multi-cell transmission scheme. In a second step, eachof the mobile terminals carries out blind detection of the S-SCH. Themapping positions of the S-SCH are the same as those of the P-SCH. Eachof the mobile terminals which has blind-detected the S-SCH can detect 10ms-timing (frame synchronization) and know the MBSFN area ID.Furthermore, the S-SCH is transmitted via a multi-cell transmissionscheme. Each of the mobile terminals receives the BCCH by using thescrambling code (Scrambling Code) related to the MBSFN area ID acquiredin the second step. Each of the mobile terminals can acquire thescheduling of the MCCH (multicast control channel) by decoding the BCCH.In this decoding process, each of the mobile terminals uses thescrambling code (Scrambling Code) related to the above-mentioned MBSFNarea ID. Furthermore, the BCCH is transmitted via a multi-celltransmission scheme. In the present invention, it is assumed that eachof the mobile terminals can acquire the system bandwidth at f(MBMS) andthe number of transmission antennas at f(MBMS) by further decoding theBCCH. In a case in which in the mobile communication system, the systembandwidth and the number of transmission antennas at f(MBMS) aredetermined statically (Static) or semi-statically (Semi-Static), therecan be provided an advantage of being able to eliminate the necessity tobroadcast the system bandwidth and/or the number of transmissionantennas at f(MBMS) from a base station to make effective use of theradio resources. Furthermore, because the necessity to change thedecoding and the parameters (the system bandwidth and/or the number oftransmission antennas at f(MBMS)) can be eliminated, there can beprovided an advantage of achieving low power consumption in each mobileterminal, and a reduction of the control delay time.

In the present invention, the scheduling of the MCCH will be furtherstudied. According to the current standards of the 3GPP, it is definedthat an MBSFN synchronization area (Multimedia Broadcast multicastservice Single Frequency Network Synchronization Area f(MBMS)) cansupport one or more MBSFN areas (MBSFN Areas) (refer to FIG. 7). Incontrast, it has not been decided how to multiplex a plurality of MBSFNareas with f(MBMS) which is a single frequency (Single Frequency).Hereafter, the “MBMS search” process in accordance with the presentinvention which is adapted in such a way as to support several differentmethods of multiplexing MBSFN areas will be explained in the case ofusing each of the different multiplexing methods.

First, a case in which time division multiplexing (TDM: Time DivisionMultiplexing) of MBSFN areas is carried out will be explained. Aconceptual diagram of the geographical location of a base station in acase in which two or more MBSFN areas exist is shown in FIG. 25. FIG. 25is an explanatory drawing showing a plurality of MBSFN areas whichconstruct an MBSFN synchronization area. In FIG. 25, the three areas:the MBSFN area 1, the MBSFN area 2, and the MBSFN area 3, exist withinthe single MBSFN synchronization area. An example of the scheduling ofthe MCCH in the BCCH acquired in step ST1725 has not been debated indetail in the 3GPP. In order to disclose a method of selecting a desiredservice in a frequency layer dedicated to MBMS transmission, and amobile communication system which enables the method to be implementedtherein, which are a challenge of the present invention, an example ofthe scheduling of the MCCH in the BCCH in the case in which timedivision multiplexing of MBSFN areas is carried out will be shown. FIG.26 is a conceptual diagram of mapping to a physical channel in the MBSFNsynchronization area when time division multiplexing of the MBSFN areasis carried out.

FIG. 26 shows a concept of time division multiplexing of channels to theplurality of MBMFN area which is carried out in the single MBSFNsynchronization area. Because the MBFSN areas included in the singleMBSFN synchronization area are synchronized with one another in time,the P-SCH (primary synchronization channel) is transmitted at the sametime within each of the MBMS dedicated cell in the MBSFN area 1, theMBMS dedicated cell in the MBSFN area 2, and the MBMS dedicated cell inthe MBSFN area 3. Furthermore, assuming that the additional sequence forexclusive use is used, the sequences of the P-SCH in all the MBSFN areasare the same as one another. Therefore, in the MBSFN synchronizationarea, identical information is transmitted at the same time by using theP-SCH. Furthermore, as mentioned above, it is considered that the MBSFNarea ID is transmitted by using the S-SCH (secondary synchronizationchannel). In this case, by using the S-SCH, information different foreach MBSFN area is transmitted at the same time in the MBSFNsynchronization area. In this case, all the MBMS dedicated cells in eachMBSFN area transmit identical information at the same time. When themobile communication system carries out transmission of data using theBCCH, the mobile communication system multiplies the data by thescrambling code related to the MBSFN area ID. This scrambling code isinformed to each of the mobile terminals by using the S-SCH (secondarysynchronization channel). Therefore, information different for eachMBSFN area is transmitted by using the BCCH at the same time in theMBSFN synchronization area. On the other hand, the contents of the BCCHare the same in all the base stations dedicated to MBMS in each MBSFNarea. By decoding the BCCH, each of the mobile terminals can acquire thescheduling of the MCCH.

As described in nonpatent reference 2, for current 3GPP communicationsystems, allocation of MBSFN subframes in an MBMS/Unicast-mixed cell hasbeen examined. In a communication system based on an LTE method, becausethere exist no subframes for unicast in an MBMS dedicated cell which isdisposed in the communication system, all the subframes in the MBMSdedicated cell are MBSFN ones. However, it is important to match theconfiguration of an MBMS/Unicast-mixed cell to that of an MBMS dedicatedcell as much as possible. To this end, a method of carrying outscheduling in an MBMS dedicated cell following the concept about the“MBSFN frame cluster” (MBSFN frame Cluster) disclosed by nonpatentreference 2 will be disclosed hereafter. In addition, the scheduling ofthe MCCH in an MBSFN subframe will also be explained. In FIG. 26, eachof cycles in which an MBSFN frame cluster is repeated are referred to asan MBSFN frame cluster repetition period (MBSFN frame Cluster RepetitionPeriod). Furthermore, each of cycles in which an MCCH is transmitted isreferred to as an MCCH repetition period (MCCH Repetition Period). Acase in which an MBSFN frame cluster is shorter than the MCCH repetitionperiod length will be explained.

In FIG. 26, it is considered that a starting point value of a time atwhich the MCCH is mapped and the MCCH repetition period length areinformed as the scheduling of the MCCH. More concretely, the number ofradio frames is used for the indication of the MCCH repetition periodlength. An SFN (System Frame Number) is used for the indication of thestarting point value. Something other than the number of radio framescan be used for the indication of the MCCH repetition period length. Asa concrete example, the number of subframes can be used for theindication of the MCCH repetition period length. Something other than anSFN can be used for the indication of the starting point value. As aconcrete example, an offset value from a certain reference value can beused for the indication of the starting point value. In a case in whichthe MCCH is mapped onto some subframes in a radio frame, an SFN, asubframe number, and so on can be informed as the starting point. Aconcrete computation expression for calculating the starting point valueis expressed by (the starting point value=(the SFN number of the leadingone of system frames onto which the MCCH is mapped) mod (the MCCHrepetition period length)). In FIG. 26, the MCCH starting point value 1of the MBSFN area 1 is 1 mod 7=1, 8 mod 7=1, or . . . , and theparameters of the MCCH scheduling of the MBSFN area 1 are the MCCHrepetition period length 1 of “7” and the starting point value 1 of “1”.Furthermore, the MCCH starting point value 2 of the MBSFN area 2 is 4mod 7=4, or . . . , and the parameters of the MCCH scheduling of theMBSFN area 2 are the MCCH repetition period length 2 of “7” and thestarting point value 2 of “4”. Furthermore, the MCCH starting pointvalue 3 of the MBSFN area 3 is 6 mod 7=6, or . . . , and the parametersof the MCCH scheduling of the MBSFN area 3 are the MCCH repetitionperiod length 3 of “7” and the offset value 3 of “6”. The SFN at thistime is broadcast for each radio frame when mapped onto the BCCH, and iseffective also when receiving the MCCH from the MCCH starting pointvalue.

That is, data which are transmitted from each base station belonging tothe MBSFN area 1 are provided as follows. The P-SCH (primarysynchronization channel) which is the above-mentioned additionalsequence for exclusive use, the S-SCH1 (secondary synchronizationchannel) onto which the MBSFN area ID1 and so on are mapped, a BCCH1onto which the MCCH starting point value 1 of “1”, the MCCH repetitionperiod length 1 of “7”, and so on are mapped, and which is multiplied bythe scrambling code 1, and an MCCH1 and an MTCH1 of the MBSFN area 1 aretransmitted. Because time division multiplexing of each base stationbelonging to the MBSFN area 1, MBSFN area 2 and MBSFN area 3 is carriedout, an MCCH2 and an MCCH3 and an MTCH2 and an MTCH3 from each basestation belonging to the MBSFN area 2 or 3 are in a discontinuoustransmission (DTX: Discontinuous transmission) state during a timeperiod during which the MBSFN area 1 is carrying out transmission. Eachof the MCCH1 and the MTCH1 can be multiplied by the scrambling code 1.By multiplying each of the MCCH1 and the MTCH1 by the scrambling code,there can be provided an advantage of unifying a process to be performedon MBSFN-area-specific data (BCCH, MCCH, and MTCH). In contrast, becausethe MCCH and the MTCH are subjected to time division multiplexing (TDM),it is not necessary to multiply each of the MCCH and the MTCH by theMBSFN-area-specific scrambling code. In the case of not multiplying eachof the MCCH1 and the MTCH1 by the scrambling code, there can be providedan advantage of reducing the load of encoding processing on each basestation side and the load of decoding process on each mobile terminalside, and hence reducing the time delay occurring before data reception.

Like in the case of the MBSFN area 1, data which are transmitted fromeach base station belonging to the MBSFN area 2 are provided as follows.The P-SCH (primary synchronization channel) which is the above-mentionedadditional sequence for exclusive use, the S-SCH2 (secondarysynchronization channel) onto which the MBSFN area ID2 and so on aremapped, a BCCH2 onto which the MCCH starting point value 2 of “4”, theMCCH repetition period length 2 of “7”, and so on are mapped, and whichis multiplied by the scrambling code 2, and the MCCH2 and the MTCH2 ofeach base station belonging to the MBSFN area 2 are transmitted. TheMCCH1 and 3 and the MTCH1 and 3 from each base station belonging to theMBSFN area 1 and 3 are in a discontinuous transmission (DTX:Discontinuous transmission) state during this time period. Like in thecase of the MBSFN area 1, data which are transmitted from each basestation belonging to the MBSFN area 3 are provided as follows. The P-SCH(primary synchronization channel) which is the above-mentionedadditional sequence for exclusive use, the S-SCH3 (secondarysynchronization channel) onto which the MBSFN area ID3 and so on aremapped, a BCCH3 onto which the MCCH starting point value 3 of “6”, theMCCH repetition period length 3 of “7”, and so on are mapped, and whichis multiplied by the scrambling code 3, and the MCCH3 and the MTCH3 ofthe MBSFN area 3 are transmitted. The MCCH1 and 2 and the MTCH1 and 2from each base station belonging to the MBSFN area 1 and 2 are in adiscontinuous transmission (DTX: Discontinuous transmission) stateduring this time period. For the sake of simplicity, an example in whichtime division multiplexing of the MCCH and the MTCH is carried out foreach radio frame is shown in FIG. 26. However, the present invention canbe applied to a case in which another method of multiplexing the MCCHand the MTCH is used, and a case in which the time division multiplexingis carried out for each of units other than each radio frame.Furthermore, as long as the MCCH repetition period length is determinedstatically (Static) or semi-statically (Semi-Static) in the mobilecommunication system, each base station does not have to broadcast theMCCH repetition period length. Therefore, because the amount ofinformation to be broadcast decreases, there can be provided anadvantage of making effective use of the radio resources.

Next, a case in which code division multiplexing (CDM: Code DivisionMultiplexing) of MBSFN areas is carried out will be explained. Aconceptual diagram showing the location of a base station in a case inwhich two or more MBSFN areas exist is the same as that in the case oftime division multiplexing (TDM). FIG. 27 is a conceptual diagram ofmapping to a physical channel in the MBSFN synchronization area whencode division multiplexing of MBSFN areas is carried out. In FIG. 27, itis assumed that an MBMS service (an MCCH and an MTCH) is transmittedcontinuously in each of the MBSFN areas. In such a case, an MBSFN framecluster does not have to be defined. A case in which an MBSFN framecluster is shorter than the MCCH repetition period length will beexplained. Because an example of a P-SCH (primary synchronizationchannel), an S-SCH (secondary synchronization channel), and a BCCH isthe same as that in the case of time division multiplexing (TDM), anexplanation of the example will be omitted hereafter. In the presentinvention, it is considered that a starting point value of a time atwhich an MCCH is mapped and the MCCH repetition period length areinformed as the scheduling of the MCCH. More concretely, the number ofradio frames is used for the indication of the MCCH repetition periodlength. An SFN (System Frame Number) is used for the indication of thestarting point value. Something other than the number of radio framescan be used for the indication of the MCCH repetition period length. Asa concrete example, the number of subframes can be used for theindication of the MCCH repetition period length. Something other than anSFN can be used for the indication of the starting point value. As aconcrete example, an offset value from a certain reference value can beused for the indication of the starting point value. In a case in whichthe MCCH is mapped onto some subframes in a radio frame, an SFN, asubframe number, and so on can be informed as the starting point. Aconcrete computation expression for calculating the starting point valueis expressed by (the starting point value=(the SFN number of the leadingone of system frames onto which the MCCH is mapped) mod (the MCCHrepetition period length)). In FIG. 27, the MCCH starting point value ofthe MBSFN area 1 is 1 mod 3=1, 4 mod 3=1, or . . . , and the parametersof the MCCH scheduling of the MBSFN area 1 are the MCCH repetitionperiod length 1 of “3” and the starting point value of “1”. The MCCHstarting point value of the MBSFN area 2 is 1 mod 2=1, 3 mod 2=1, or . .. , and the parameters of the MCCH scheduling of the MBSFN area 1 arethe MCCH repetition period length 2 of “2” and the starting point valueof “1”. The MCCH starting point value of the MBSFN area 3 is 2 mod 4=2,or . . . , and the parameters of the MCCH scheduling of the MBSFN area 3are the MCCH repetition period length 3 of “4” and the starting pointvalue of “2”.

That is, data which are transmitted from each base station belonging tothe MBSFN area 1 are provided as follows. The P-SCH (primarysynchronization channel) which is the sequence intended for thefrequency layer dedicated to MBMS transmission (the above-mentionedadditional sequence for exclusive use), the S-SCH1 (secondarysynchronization channel) onto which the MBSFN area ID1 and so on aremapped, a BCCH1 onto which the MCCH starting point value 1 of “1”, theMCCH repetition period length 1 of “3”, and so on are mapped, and whichis multiplied by the scrambling code 1, and an MCCH1 and an MTCH1 ofeach base station belonging to the MBSFN area 1, each of which ismultiplied by the scrambling code 1, are transmitted. Like in the caseof the MBSFN area 1, data which are transmitted from each base stationbelonging to the MBSFN area 2 are provided as follows. The P-SCH(primary synchronization channel) which is the sequence intended for thefrequency layer dedicated to MBMS transmission, the S-SCH2 (secondarysynchronization channel) onto which the MBSFN area ID2 and so on aremapped, a BCCH2 onto which the MCCH starting point value 2 of “1”, theMCCH repetition period length 2 of “2”, and so on are mapped, and whichis multiplied by the scrambling code 2, and an MCCH2 and an MTCH2 ofeach base station belonging to the MBSFN area 2, each of which ismultiplied by the scrambling code 2, are transmitted. Like in the caseof the MBSFN area 1, data which are transmitted from each base stationbelonging to the MBSFN area 3 are provided as follows. The P-SCH(primary synchronization channel) which is the sequence intended for thefrequency layer dedicated to MBMS transmission, the S-SCH3 (secondarysynchronization channel) onto which the MBSFN area ID3 and so on aremapped, a BCCH3 onto which the MCCH starting point value 3 of “2”, theMCCH repetition period length 3 of “4”, and so on are mapped, and whichis multiplied by the scrambling code 3, and an MCCH3 and an MTCH3 ofeach base station belonging to the MBSFN area 3, each of which ismultiplied by the scrambling code 3, are transmitted.

For the sake of simplicity, an example in which time divisionmultiplexing of the MCCH and the MTCH is carried out for each radioframe is shown in FIG. 27. However, the present invention can be appliedto a case in which another method of multiplexing the MCCH and the MTCHis used, and a case in which the time division multiplexing is carriedout for each of units other than each radio frame. Furthermore, as longas the MCCH repetition period length is determined statically (Static)or semi-statically (Semi-Static) in the mobile communication system, anybase station does not have to broadcast the MCCH repetition periodlength. Therefore, because the amount of information to be broadcastdecreases, there can be provided an advantage of making effective use ofthe radio resources. In the case in which code division multiplexing(CDM) of MBSFN areas is carried out, because a different repetitionperiod length can be set up for each of the MBSFN areas, there isprovided an advantage of being able to carry out scheduling with highflexibility for MBMS services as compared with the case in which timedivision multiplexing (TDM) of MBSFN areas is carried out. In addition,because the code division multiplexing is used, even when MTCHs andMCCHs from a plurality of MBSFN areas coincide simultaneously at amobile terminal, the mobile terminal can separate them from one another(because the mobile terminal can separate them from one another by usingthe scrambling codes). Therefore, because the mobile communicationsystem can transmit MTCHs and MCCHs from the MBSFN areas 1 to 3simultaneously, there can be provided an advantage of expanding thefrequency and time radio resources which are allocated to one MBSFNarea.

Next, an explanation will be made as to a study to dispose an MBSFN areacovering a plurality of MBSFN areas which has been made in the currentdebate of the 3GPP. FIG. 28 is an explanatory drawing showing aplurality of MBSFN areas which construct an MBSFN synchronization area,and is an explanatory drawing showing an MBSFN area covering a pluralityof MBSFN areas. In FIG. 28, four MBSFN areas 1 to 4 exist in a singleMBSFN synchronization area (MBSFN Synchronization Area). Among the fourMBSFN areas, the MBSFN area 4 covers the MBSFN areas 1 to 3. Although ithas been debated that this MBSFN area 4 is accessed via one of the MBSFNareas 1 to 3 covered by the MBSFN area 4, more detailed information hasnot been decided yet. Therefore, a method of accessing an MBSFN areacovering a plurality of MBSFN areas will be explained hereafter.

As previously mentioned, because no more detailed decision has been madeas to a multiplexing method of multiplexing MBSFN areas, a case in whichtime division multiplexing of the MBSFN area 4 and the MBSFN areas 1 to3 covered by this MBSFN area 4 is carried out, and code divisionmultiplexing of the MBSFN areas 1 to 3 covered by the MBSFN area 4 isthen carried out will be explained first. An example of step ST1725(refer to FIG. 18) in the case in which the MBSFN areas havegeographical locations as shown in FIG. 28 will be shown. In a firststep, each of the mobile terminals carries out blind detection of aP-SCH (a primary synchronization channel) in the above-mentionedsequence for exclusive use. Therefore, each of the mobile terminalswhich has blind-detected the P-SCH can carry out 5 ms-timing detection.Furthermore, multi-cell transmission of the P-SCH is carried out. Basestations located in the MBSFN synchronization area are synchronized withone another for multi-cell transmission. Therefore, the multi-celltransmission of the P-SCH is targeted for the base stations included inthe synchronization area. In a second step, each of the mobile terminalscarries out blind detection of an S-SCH (secondary synchronizationchannel). Each of the mobile terminals which has blind-detected an S-SCHcan detect 10 ms-timing (frame synchronization) and know an MBSFN areaID. Furthermore, the S-SCH is transmitted via a multi-cell transmission.The MBSFN area ID at this time are the one of an MBSFN area covered. Indetail, the MBSFN area ID at this time is the one of either one of thecovered MBSFN area in which the mobile terminal is being located (i.e.,either of the MBSFN areas 1 to 3). Therefore, the multi-celltransmission of the S-SCH is targeted for base stations included in eachof the MBSFN areas covered. Each of the mobile terminals receives theBCCH (broadcast control channel) by using the scrambling code related tothe MBSFN area ID acquired in the second step. By decoding the BCCH,each of the mobile terminals can acquire the scheduling of an MCCH(multicast control channel). Furthermore, the BCCH is transmitted via amulti-cell transmission. Since the scrambling code acquired in thesecond step is used, the BCCH is the one from the MBSFN area covered.Therefore, the multi-cell transmission of the BCCH is targeted for basestations included in each of the MBSFN areas covered. Each of the mobileterminals can acquire the scheduling of the MCCH, the system bandwidthat f(MBMS), the number of transmission antennas, etc. by decoding theBCCH.

Hereafter, the scheduling of the MCCH will be further examined. FIG. 29is an explanatory drawing showing mapping to a physical channel in theMBSFN synchronization area in a case in which time division multiplexingof the MBSFN area (i.e., the MBSFN area 4) covering the other MBSFNareas, and the other MBSFN areas (i.e., the MBSFN areas 1 to 3) coveredis carried out, and code division multiplexing is used as a multiplexingmethod of multiplexing the MBSFN areas covered. Because the MBSFNsynchronization area is synchronous in time, the P-SCH (primarysynchronization channel) is transmitted at the same time from MBMSdedicated cells in each of the MBSFN areas 1 to 3. Furthermore, assumingthat the above-mentioned sequence exclusively used for the frequencylayer dedicated to MBMS transmission (the above-mentioned additionalsequence for exclusive use) is used, the sequences of the P-SCHs (theprimary synchronization channel) in all the MBSFN areas are the same asone another. Therefore, in the MBSFN synchronization area, identicalinformation is transmitted at the same time by using the P-SCH. Asmentioned above, it is considered that an MBSFN area ID is transmittedby using the S-SCH (the secondary synchronization channel). In thiscase, by using the S-SCH, information different for each MBSFN area istransmitted at the same time in the MBSFN synchronization area. In thiscase, all the MBMS dedicated cells in each MBSFN area transmit identicalinformation at the same time. It is assumed that at that time, there isno S-SCH specific to the MBSFN area (the MBSFN area 4) covering theother MBSFN areas. The S-SCH uses the same radio resources in frequencyand in time in the MBSFN synchronization area. Furthermore, because theS-SCH is used for a search for an MBSFN area ID related to each MBSFNarea scrambling code, the S-SCH cannot be multiplied by the scramblingcode of each MBSFN area. Non-transmission of the S-SCH to the MBSFN areacovering the other MBSFN areas means that what is necessary is just totransmit one type of S-SCH in overlapping MBSFN areas (e.g., the MBSFNareas 1 and 4) in the geographical locations where the plurality ofMBSFN areas overlap one another. As a result, the S-SCHs from the pluralMBSFN areas can be prevented from interfering with one another. Themobile communication system transmits a BCCH multiplied by thescrambling code related to an MBSFN area ID which the mobilecommunication system informs by using the S-SCH. Therefore, in thiscase, by using the BCCH, information different for each MBSFN areacovered is transmitted at the same time in the MBSFN synchronizationarea. The contents of the BCCH are the same in all the MBMS-dedicatedbase stations in each MBSFN area. By decoding the BCCH, each of themobile terminals can acquire the scheduling of the MCCH. An example ofthe scheduling of the MCCH has not been discussed in the 3GPP. In thepresent invention, an example of the scheduling of the MCCH will beshown.

Referring to FIG. 29, the scheduling of the MCCH in the case in which anMBSFN frame cluster is longer than the MCCH repetition period lengthwill also be explained. As the scheduling of the MCCH of the MBSFN areacovering the other MBSFN areas, two steps will be considered. In thefollowing explanation, for the sake of simplicity, a case in which amobile terminal is located in an MBSFN area 1 which is one MBSFN areacovered, and there exists an MBSFN area 4 as an MBSFN area covering theother MBSFN areas including the MBSFN area 1 will be explained. In afirst step, the MCCH scheduling of the MBSFN area 1 is informed by usingthe BCCH of the MBSFN area 1. In the present invention, an example ofthe scheduling of the MCCH is shown. In the present invention, there isconsidered a case in which, as the scheduling of the MCCH, the startingpoint value at the time when the MCCH is mapped and the MBSFN framecluster repetition period length, and the MCCH transmission frequencyduring the MBSFN frame cluster repetition period are informed. Moreconcretely, the number of radio frames is used as the MBSFN framecluster repetition period length. More concretely, an SFN (System FrameNumber) is used for the indication of the starting point value.Something other than the number of radio frames can be used for theindication of the MBSFN frame cluster repetition period length. As aconcrete example, the number of subframes can be used for the indicationof the MBSFN frame cluster repetition period length. Something otherthan an SFN can be used for the indication of the starting point value.As a concrete example, an offset value from a certain reference valuecan be used for the indication of the starting point value. In a case inwhich the MCCH is mapped onto some subframes in a radio frame, an SFN, asubframe number, and so on can be informed as the starting point. Aconcrete computation expression for calculating the starting point valueis expressed by (the starting point value=(the SFN number of the leadingone of system frames onto which the MCCH is mapped) mod (the MBSFN FRAMECluster Repetition Period)). More concretely, the MCCH transmissionfrequency (referred to as N_(MCCH) from here on) in the MBSFN framecluster is used as the MCCH transmission frequency within the MBSFNframe cluster repetition period. A concrete computation expression forcalculating the N_(MCCH) is expressed by (N_(MCCH)=the MBSFN framecluster length/the MCCH repetition period (MCCH Repetition Period)length. In FIG. 29, the MCCH offset value 1 of the MBSFN area 1 is 1 mod10=1. The MCCH starting point value 2 of the MBSFN area 2 is 1 mod 10=1.The MCCH starting point value 4 of the MBSFN area 4 is 7 mod 10=7. Next,N_(MCCH)1 of the MBSFN area 1 is 6/2=3. Furthermore, N_(MCCH)2 of theMBSFN area 2 is 6/3=2. N_(MCCH)4 of the MBSFN area 4 is s 4/2=2.Therefore, the parameters of the scheduling of the MCCH of the MBSFNarea 1 are the MBSFN frame cluster repetition period length 1 of “10”,the starting point value 1 of “1”, and N_(MCCH)1 of “3”. At this time,instead of informing N_(MCCH)1 as one of the parameters, the MBSFN framecluster 1 and the MCCH repetition period length 1 can be informed.

In a second step, the scheduling of the MCCH of the MBSFN area 4 isinformed by using the MCCH of the MBSFN area 1. In an example of thescheduling of the MCCH, in addition to the above-mentioned parameters ofthe MBSFN area 4 (the MBSFN frame cluster repetition period length 4 of“10”, the starting point 4 of “7”, and N_(MCCH)4 of “2”), the MBSFN areaID of the covering MBSFN area (i.e., the MBSFN area 4) is informed. Acase of including a single step as the MCCH scheduling of the MBSFN area4 can be alternatively considered. In detail, there can be considered amethod of also informing the above-mentioned MCCH scheduling of theMBSFN area 4 by using the BCCH of the MBSFN area 1. As a result, becausea mobile terminal receiving a service of the MBSFN area 4 does not haveto carry out the process of receiving and decoding the MCCH of the MBSFNarea 1, there can be provided an advantage of reducing the controldelay. The method of using, as the MCCH scheduling, the above-mentionedstarting point, the MBSFN frame cluster repetition period length, andN_(MCCH) (alternatively, the MBSFN frame cluster length and the MCCHrepetition period length) can be applied also to a case in which theMCCH exists multiple times in the MBSFN frame cluster when time divisionmultiplexing of the MBSFN areas is carried out (refer to FIG. 26).

More specifically, data transmitted from each base station belonging tothe MBSFN area 1 are provided as follows. The P-SCH (the primarysynchronization channel) which is the sequence intended for thefrequency layer dedicated to MBMS transmission, the S-SCH1 (thesecondary synchronization channel) onto which the MBSFN area ID1 and soon are mapped, a BCCH1 onto which the MCCH starting point value 1 of“1”, the MBSFN frame cluster repetition period length 1 of “10”,N_(MCCH)1 of “3”, and so on are mapped, and which is multiplied by thescrambling code 1, and an MCCH1 and an MTCH1 of the MBSFN area 1 each ofwhich is multiplied by the scrambling code 1 are transmitted. By usingthe MCCH1, the MBSFN area ID (the MBSFN area 4) of the MBSFN area 4, andthe MCCH starting point value 4 of “7”, the MBSFN frame clusterrepetition period length 4 of “10” and N_(MCCH)4 of “2”, which are thedata about the MCCH scheduling of the MBSFN area 4, are transmitted.Like in the case of the MBSFN area 1, data which are transmitted fromeach base station belonging to the MBSFN area 2 are provided as follows.The P-SCH which is the sequence intended for the frequency layerdedicated to MBMS transmission, the S-SCH2 onto which the MBSFN area ID2and so on are mapped, a BCCH2 onto which the MCCH starting point value 2of “1”, the MBSFN frame cluster repetition period length 2 of “10”,N_(MCCH)2 of “2”, and so on are mapped, and which is multiplied by thescrambling code 2, and an MCCH2 and an MTCH2 of the MBSFN area 2 each ofwhich is multiplied by the scrambling code 2 are transmitted. By usingthe MCCH2, the MBSFN area ID (the MBSFN area 4) of the MBSFN area 4, andthe MCCH offset value 4 of “7”, the MBSFN frame cluster repetitionperiod length 4 of “10” and N_(MCCH)4 of “2”, which are the data aboutthe MCCH scheduling of the MBSFN area 4, are transmitted.

As explained previously, the data transmission from the MBSFN area 4does not include transmission of the P-SCH and the S-SCH. In addition,when it is not necessary to inform, as the system information about theMBSFN area 4, any information other than what is transmitted by usingthe BCCH of each of the covered MBSFN areas (the MBSFN areas 1 to 3),the transmission of the BCCH from the MBSFN area 4 can be omitted. As aresult, there can be provided an advantage of making effective use ofthe radio resources. An MCCH4 and an MTCH4 of the MBSFN area 4 each ofwhich is not multiplied by any scrambling code are transmitted.

For the sake of simplicity, the example in which time divisionmultiplexing of the MCCH and the MTCH is carried out for each radioframe is shown in FIG. 29. However, the present invention can be appliedto a case in which another method of multiplexing the MCCH and the MTCHis used, and a case in which the time division multiplexing is carriedout for each of units other than each radio frame. The multiplexingmethod of carrying out time division multiplexing of the MBSFN area (theMBSFN area 4) covering the other MBSFN areas, and the other MBSFN areas(the MBSFN areas 1 to 3) covered, and then carrying out code divisionmultiplexing of the covered MBSFN areas uses code division multiplexingas the multiplexing method of multiplexing the MBSFN areas 1 to 3 whichare separated from the viewpoint of their geographical locations. As aresult, there can be provided an advantage of making effective use ofthe radio resources both in frequency and in time. In the code divisionmultiplexing, because the demultiplexing of the MBSFN areas is carriedout by using only the scrambling code allocated to each MBSFN area,there is a possibility that transmission data transmitted from the MBSFNareas interfere with one another. In contrast, in accordance with thepresent multiplexing method, there is provided an advantage of, even ifcode division multiplexing is used to multiplex transmission data fromthe MBSFN areas 1 to 3 which are separated from the viewpoint of theirgeographical locations, making it difficult for interference amongtransmission data from the MBSFN areas 1 to 3 to occur. Time divisionmultiplexing is used to multiplex transmission data from the MBSFN area4 and transmission data from the MBSFN areas 1 to 3, the MBSFN area 4and the MBSFN areas to 3 being not separated from the viewpoint of theirgeographical locations. As a result, the multiplexing method ofmultiplexing transmission data from the MBSFN area 4 and transmissiondata from the MBSFN areas 1 to 3, which originally allows interferenceto easily occur because the MBSFN area 4 and the MBSFN areas 1 to 3 arenot separated from the viewpoint of their geographical locations, can bemodified to make it difficult for interference between transmission datafrom the MBSFN area 4 and transmission data from the MBSFN areas 1 to 3to occur. By using this multiplexing method, there can be provided anadvantage of being able to make effective use of the radio resourceswhile preventing interference among transmission data from the MBSFNareas. Furthermore, in the covering MBSFN area (the MBSFN area 4), theP-SCH, the S-SCH, and the BCCH can be eliminated by not carrying out asearch for an MBMS. As a result, there can be provided an advantage ofbeing able to make effective use of the radio resources of the MBSFNarea 4.

Next, an example in a case in which time division multiplexing of theMBSFN area (i.e., the MBSFN area 4) covering the other MBSFN areas, andthe other MBSFN areas (i.e., the MBSFN areas 1 to 3) covered by theMBSFN area 4 is carried out, and time division multiplexing is also usedas the method of multiplexing the covered MBSFN areas will be explained.A conceptual diagram showing the locations of base stations in the casein which the plurality of MBSFN areas exist is the same as that in thecase in which time division multiplexing of the MBSFN area (i.e., theMBSFN area 4) covering the other MBSFN areas, and the other MBSFN areas(i.e., the MBSFN areas 1 to 3) covered by the MBSFN area 4 is carriedout, and code division multiplexing is used as the method ofmultiplexing the covered MBSFN areas. Because the explanation about theP-SCH, the S-SCH, and the BCCH is the same as that in theabove-mentioned case, the explanation will be omitted. Because anexample of the scheduling of the MCCH is much the same as that in theabove-mentioned case, an explanation will be made focusing on adifferent portion. In a first step, the MCCH scheduling of the MBSFNarea 1 is informed by using the BCCH of the MBSFN area 1. In the presentinvention, an example of the scheduling of the MCCH is shown. In thepresent invention, there is considered a case in which, as thescheduling of the MCCH, the starting point value at the time when theMCCH is mapped and the MCCH repetition period length are informed. Thenumber of radio frames is used for the indication of the MCCH repetitionperiod length. More concretely, an SFN (System Frame Number) is used forthe indication of the starting point value. Something other than thenumber of radio frames can be used for the indication of the MCCHrepetition period length. As a concrete example, the number of subframescan be used for the indication of the MCCH repetition period length.Something other than an SFN can be used for the indication of thestarting point value. As a concrete example, an offset value from acertain reference value can be used for the indication of the startingpoint value. In a case in which the MCCH is mapped onto some subframesin a radio frame, an SFN, a subframe number, and so on can be informedas the starting point. A concrete computation expression for calculatingthe starting point value is given by (the starting point value=(the SFNnumber of the leading one of system frames onto which the MCCH ismapped) mod (the MCCH repetition period length). In a second step, thescheduling of the MCCH of the MBSFN area 4 is informed by using the MCCHof the MBSFN area 1. In the example of the scheduling of the MCCH, theMBSFN area ID (the MBSFN area 4) of the covering MBSFN area is informedin addition to the parameters of the MBSFN area 4 which are the same asthe above-mentioned parameters of the MBSFN area 1. The explanation ofthe parameters of the MBSFN area 4 will be omitted hereafter.

Next, an example in a case in which code division multiplexing of theMBSFN area (i.e., the MBSFN area 4) covering the other MBSFN areas, andthe other MBSFN areas (i.e., the MBSFN areas 1 to 3) covered by theMBSFN area 4 is carried out, and code division multiplexing is also usedas the method of multiplexing the covered MBSFN areas will be explained.A conceptual diagram showing the locations of base stations in the casein which the plurality of MBSFN areas exist is the same as that in thecase in which time division multiplexing of the MBSFN area (i.e., theMBSFN area 4) covering the other MBSFN areas, and the other MBSFN areas(i.e., the MBSFN areas 1 to 3) covered by the MBSFN area 4 is carriedout, and code division multiplexing is used as the method ofmultiplexing the covered MBSFN areas. Because the explanation about theP-SCH, the S-SCH, and the BCCH is the same as that in theabove-mentioned case, the explanation will be omitted. Because anexample of the scheduling of the MCCH is much the same as that in theabove-mentioned case, an explanation will be made focusing on adifferent portion. In a first step, the MCCH scheduling of the MBSFNarea 1 is informed by using the BCCH of the MBSFN area 1. In the presentinvention, an example of the scheduling of the MCCH is shown. In thepresent invention, there is considered a case in which, as thescheduling of the MCCH, the starting point value at the time when theMCCH is mapped and the MCCH repetition period length are informed. Thenumber of radio frames is used for the indication of the MCCH repetitionperiod length. More concretely, an SFN (System Frame Number) is used forthe indication of the starting point value. Something other than thenumber of radio frames can be used for the indication of the MCCHrepetition period length. As a concrete example, the number of subframescan be used for the indication of the MCCH repetition period length.Something other than an SFN can be used for the indication of thestarting point value. As a concrete example, an offset value from acertain reference value can be used for the indication of the startingpoint value. In a case in which the MCCH is mapped onto some subframesin a radio frame, an SFN, a subframe number, and so on can be informedas the starting point. A concrete computation expression for calculatingthe starting point value is given by (the starting point value=(the SFNnumber of the leading one of system frames onto which the MCCH ismapped) mod (the MCCH repetition period length). In a second step, thescheduling of the MCCH of the MBSFN area 4 is informed by using the MCCHof the MBSFN area 1. In the example of the scheduling of the MCCH, theMBSFN area ID (i.e., the MBSFN area 4) of the covering MBSFN area isinformed in addition to the parameters of the MBSFN area 4 which are thesame as the above-mentioned parameters of the MBSFN area 1. Theexplanation of the parameters of the MBSFN area 4 will be omittedhereafter. The scrambling code used in the MBSFN area 4 is determined onthe basis of the MBSFN area ID (the MBSFN area 4) informed thereto byusing the MCCH1 of the MBSFN area 1.

Next, an example in a case in which code division multiplexing of theMBSFN area (i.e., the MBSFN area 4) covering the other MBSFN areas, andthe other MBSFN areas (the MBSFN areas 1 to 3) covered by the MBSFN area4 is carried out, and time division multiplexing is used as the methodof multiplexing the covered MBSFN areas will be explained. A conceptualdiagram showing the locations of base stations in the case in which theplurality of MBSFN areas exist is the same as that in the case in whichtime division multiplexing of the MBSFN area (i.e., the MBSFN area 4)covering the other MBSFN areas, and the other MBSFN areas (i.e., theMBSFN areas 1 to 3) covered by the MBSFN area 4 is carried out, and codedivision multiplexing is used as the method of multiplexing the coveredMBSFN areas. Because the explanation about the P-SCH, the S-SCH, and theBCCH is the same as that in the above-mentioned case, the explanationwill be omitted. Because an example of the scheduling of the MCCH ismuch the same as that in the above-mentioned case, an explanation willbe made focusing on a different portion. In a first step, the MCCHscheduling of the MBSFN area 1 is informed by using the BCCH of theMBSFN area 1. In the present invention, an example of the scheduling ofthe MCCH is shown. In the present invention, there is considered a casein which, as the scheduling of the MCCH, the starting point value at thetime when the MCCH is mapped and the MCCH repetition period length areinformed. The number of radio frames is used for the indication of theMCCH repetition period length. More concretely, an SFN (System FrameNumber) is used for the indication of the starting point value.Something other than the number of radio frames can be used for theindication of the MCCH repetition period length. As a concrete example,the number of subframes can be used for the indication of the MCCHrepetition period length. Something other than an SFN can be used forthe indication of the starting point value. As a concrete example, anoffset value from a certain reference value can be used for theindication of the starting point value. In a case in which the MCCH ismapped onto some subframes in a radio frame, an SFN, a subframe number,and so on can be informed as the starting point. A concrete computationexpression for calculating the starting point value is given by (thestarting point value=(the SFN number of the leading one of system framesonto which the MCCH is mapped) mod (the MCCH repetition period length).In a second step, the scheduling of the MCCH of the MBSFN area 4 isinformed by using the MCCH of the MBSFN area 1. In the example of thescheduling of the MCCH, as the parameters of the MBSFN area 4, thestarting point, the MCCH repetition period length, and the MBSFN area ID(the MBSFN area 4) of the covering MBSFN area are informed.

In all of the above-mentioned multiplexing methods of multiplexing theMBSFN areas, the starting point of the MCCH in the MCCH scheduling canbe replaced by either an MCH starting point or a PMCH starting point. Ina case in which the starting point of the MCCH is replaced by an MCHstarting point, instead of the MCCH repetition period length parameterin the MCCH scheduling, an MCH repetition period length is provided. Atthat time, in a case in which an MCCH is always mapped to each MCH, theMCH repetition period length is equal to the MCCH repetition periodlength. In contrast, when an MCCH is not always mapped to each MCH, theMCCH repetition period length, together with the MCH repetition periodlength, can be provided as a parameter. In a case in which the startingpoint of the MCCH is replaced by a PMCH starting point, instead of theMCCH repetition period length parameter in the MCCH scheduling, a PMCHrepetition period length is provided. At that time, in a case in whichan MCCH is always mapped to each PMCH, the PMCH repetition period lengthis equal to the MCCH repetition period length. In contrast, when an MCCHis not always mapped to each PMCH, the MCCH repetition period length,together with the PMCH repetition period length, can be provided as aparameter.

In the 3GPP, a debate has been furthered towards supporting single-celltransmission in a frequency layer dedicated to MBMS transmission. As amethod of supporting single-cell transmission, a method of implementingsingle-cell transmission in an MBSFN area consisting of a single cellhas been examined. However, any concrete method of implementingsingle-cell transmission in an MBSFN area consisting of a single cellhas not been examined at all. In order to disclose a method of selectinga desired service in a frequency layer dedicated to MBMS transmission,and a mobile communication system which enables the method to beimplemented therein, which are a challenge of the present invention, anexample of the method of supporting single-cell transmission will beshown. An concrete example of the implementation in the case in which anMBSFN area covering a plurality of MBSFN areas exists is explainedabove. By replacing each of cells within the covered MBSFN areas (i.e.,the MBSFN areas 1 to 3) with a cell which carries out single-cell(Single-cell) transmission and further replacing the MBSFN area (i.e.,the MBSFN area 4) covering the other MBSFN areas with a cell whichcarries out multi-cell (multi-cell) transmission in the above-mentionedmethod, single-cell transmission can be implemented in an MBSFN areaconsisting of a single cell.

Next, “MBMS area information acquisition” described in Embodiment 1 willbe explained more concretely with reference to steps ST1726 and ST1727of FIG. 18, and steps ST1728 and ST1729 of FIG. 19. It is assumed thatthe MCCH (multicast control channel) of each MBSFN area is transmittedvia a multi-cell transmission scheme. Therefore, an MCE, in step ST1726,transmits information about allocation of radio resources fortransmitting the contents of the MCCH and the MCCH to base stations inthe MBSFN area. Each MBMS-dedicated base station, in step ST1727,receives the information about allocation of radio resources fortransmitting the contents of the MCCH and the MCCH from the MCE. Eachbase station, in step ST1728, carries out multi-cell transmission ofcontrol information, such as MBMS area information, discontinuousreception (DRX) information, and the number K of paging groups, by usingthe MCCH according to the radio resources allocated thereto by the MCE.Each of the mobile terminals, in step ST1729, receives the MCCH fromeach base station in the MBSFN area. Each of the mobile terminals usesthe scheduling of the MCCH received from the network side in step ST1725for the reception of the MCCH.

An example of the receiving method will be explained. As a typicalexample, a case in which a plurality of base stations are arranged asshown in FIG. 25, and time division multiplexing of each MBSFN area iscarried out as shown in FIG. 26 will be explained. A case in which eachof the mobile terminals is located within the MBSFN area 1 will beexplained. Each of the mobile terminals decodes the BCCH1 (broadcastcontrol channel) of the MBSFN area 1 to receive, as the schedulingparameters of the MCCH1, the starting point value 1 of “1” and the MCCHrepetition period (MCCH Repetition Period) length 1 of “7”. Furthermore,if an SFN (System Frame Number) is mapped onto the BCCH, each of themobile terminals can know the SFN number by decoding the BCCH. Each ofthe mobile terminals can determine the SFN number onto which the MCCH ismapped according to the following equation.SFN=the MCCH repetition period length 1×α+the starting point value 1(αis a positive integer).

Each of the mobile terminals can receive the MCCH1 by receiving anddecoding the radio resources of the SFN number onto which the MCCH1 ismapped. Control information for MBMS service which is transmitted via amulti-cell transmission scheme from the MBSFN area 1 is mapped onto theMCCH1. As an example of the control information, there are MBMS areainformation, DRX information, parameters for discontinuous reception atthe time of MBMS reception, etc.

In addition, an example of the MBMS area information will be explainedwith reference to FIG. 26. As the MBMS area information, there can beconsidered the frame structure of each area (an MBSFN frame cluster(MBSFN frame Cluster), an MBSFN subframe, etc.), contents of services,modulation information about the MTCH, etc. As the MBSFN frame cluster1, the number of frames included in a set of frames allocated to theMBSFN area 1 during one MBSFN frame cluster repetition period isinformed. As the MBSFN subframe 1, the number of a subframe onto whichMBMS data (MTCH and/or MCCH data) are actually mapped in one radio framewithin the MBSFN frame cluster 1 is informed. In a case of offering anMBMS service using an MBMS-dedicated base station, it is not necessaryto share radio resources with unicast data, unlike in a case of using anMBMS/Unicast-mixed cell. Therefore, MBMS data can be mapped onto all thesubframes in one radio frame (however, except portions onto which aP-SCH, an S-SCH, or a BCCH is mapped). In a case of mapping MBMS dataonto all the subframes, it is not necessary to inform the parameterabout MBSFN subframes from the network side to the mobile terminal side.As a result, effective use of the radio resources can be made. As analternative, because by using a method of statically mapping MBMS dataonto all the subframes at the time of transmission of MBMS data from anMBMS dedicated cell in the radio communication system, it becomes ableto transmit large-volume MBMS data and it becomes unnecessary to alsoinform the parameter about MBSFN subframes, effective use of the radioresources can be made. As the contents of services, the contents of MBMSservices being ongoing in the MBMS area 1 are informed. When a pluralityof MBMS services (a movie, sports live broadcasting, etc.) are ongoingin the MBSFN area 1, the contents of the plurality of MBMS services andparameter for multiplexing about these services are informed.

FIG. 30 is an explanatory drawing showing a relationship between a DRXperiod during which transmission of MBMS data to a mobile terminal isdiscontinued and the mobile terminal does not perform its receivingoperation of receiving the MBMS data, and a DRX cycle which is a cyclein which the DRX period is repeated. In addition, an example of DRX(Discontinuous reception) information will be explained with referenceto FIG. 30. In order to inform a paging signal to a mobile terminalcurrently using an MBMS service in an MBMS transmission dedicated cell,which is a challenge of the present invention, the mobile terminalcurrently receiving the MBMS service in the MBMS transmission dedicatedcell needs to carry out a location registration into the network viaeither a unicast cell or an MBMS/Unicast-mixed cell, and so on. To thisend, a measurement of either the unicast cell or the MBMS/Unicast-mixedcell and a location registration (a re-selection of a serving basestation (a cell re-selection)) are required. As a result, there can beprovided an advantage of becoming able to ensure the mobility in theMBMS dedicated cells in which no uplink exists via the unicast/mixedcell. Therefore, there is provided an advantage of enabling even amobile terminal currently receiving an MBMS service in a frequency layerdedicated to MBMS transmission to receive a paging signal. Therefore,even a mobile terminal currently receiving an MBMS service in an MBMStransmission dedicated cell needs to carry out a measurement of aunicast cell and an MBMS/Unicast-mixed cell at constant periods (orcycles). According to a conventional method (3GPP W-CDMA), the length ofa measurement cycle is an integral multiple of the length of adiscontinuous reception cycle, and is informed from the network side toeach mobile terminal by way of an upper layer.

A problem is therefore that, assuming that a mobile terminal currentlyreceiving an MBMS service in an MBMS transmission dedicated cell carriesout a measurement of an unicast cell and an MBMS/Unicast-mixed cell atmeasurement periods (or cycles) of the length informed from an upperlayer by using the conventional method, because a base station whichconstructs an MBSFN synchronization area of a frequency layer dedicatedto MBMS transmission, and a base station which constructs aunicast/mixed frequency layer are asynchronous to each other(asynchronous), the mobile terminal has to interrupt the MBMS receptionin order to carry out the measurement.

Therefore, in accordance with the present invention, as a solution ofthe above-mentioned problem, one DRX period is disposed in the MBSFNsynchronization area (refer to FIG. 30). A DRX period in this Embodiment1 means a time period during which transmission of MBMS data about theMBMS services of all the MBSFN areas in the MBSFN synchronization areafrom the network side to a mobile terminal is discontinued and is notcarried out, i.e., a time period during which reception of MBMS data isnot carried out when viewed from the mobile terminal side. Therefore, amobile terminal currently using an MBMS service in a frequency layerdedicated to MBMS transmission is provided

an advantage of eliminating the necessity to interrupt the use of theMBMS service by carrying out a measurement of a unicast cell and anMBMS/Unicast-mixed cell during the DRX period during which no MBMS dataare transmitted from the network side. Furthermore, by disposing a DRXperiod in the MBSFN synchronization area, each mobile terminal isenabled to simultaneously receive MBMS data from MBSFN areas in theMBSFN synchronization area without adding any control operation.

Next, the DRX cycle as shown in FIG. 30 will be explained. The DRX cyclemeans a cycle in which a DRX period explained previously is repeated.According to a conventional method, a measurement period length is set(informed) to each mobile terminal by the network side. In a case inwhich this method is applied also to LTE, if a mobile terminal currentlyreceiving an MBMS service in a frequency layer dedicated to MBMStransmission carries out a measurement in a unicast/mixed frequencylayer during a DRX period, the information about the length of the DRXcycle and the length of the DRX period in the frequency layer dedicatedto MBMS transmission needs to be notified, via one of routes, to acontrol device (abase station, an MME, a PDNGW, or the like) on a sideof a unicast cell or an MBMS/Unicast-mixed cell. Furthermore, becausebase stations which construct the unicast/mixed frequency layer areconfigured in such a way as to be fundamentally asynchronous to oneanother, there is a necessity to inform both the DRX cycle length andthe DRX period length in the frequency layer dedicated to MBMStransmission to each unicast cell or each MBMS/Unicast-mixed cell. Thismethod makes the mobile communication system become complicated, andtherefore is not preferred. Therefore, in the present invention, thefollowing method will be disclosed.

One or more measurement periods in the unicast/mixed frequency layer aremade to be included in one DRX period in the frequency layer dedicatedto MBMS transmission. As a result, even if any measurement period lengthis informed (set) to the mobile terminal from a unicast cell or anMBMS/Unicast-mixed cell, when the mobile terminal carries out ameasurement of the unicast/mixed frequency layer during a DRX periodwhich is provided in the DRX cycle in the frequency layer dedicated toMBMS transmission, the measurement period length informed from thenetwork side can be satisfied. By using this method, any control deviceof an MBMS transmission dedicated cell (a base station, an MCE, an MBMSgateway, an eBNSC, and so on) does not have to inform the DRX cyclelength and the DRX period length in the MBMS transmission dedicated cellto control devices of a unicast cell and an MBMS/Unicast-mixed cell.Therefore, there is provided an advantage of enabling a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBSFN transmission to carry out a measurement at measurement periods ofa length which a unicast cell or an MBMS/Unicast-mixed cell has informed(set) to the mobile terminal while preventing the mobile communicationsystem from becoming complicated, that is, avoiding addition ofsignaling onto a wireless interface or into the network.

The DRX cycle in the MBMS transmission dedicated cell has a length whichis either a minimum of the measurement period length which can beprovided in a unicast cell and in a unicast/mixed cell, or an integralsubmultiple of the minimum. In a case in which the measurement periodlength which a unicast cell or an MBMS/Unicast-mixed cell can set to amobile terminal currently receiving an MBMS service in the frequencylayer dedicated to MBMS transmission differs from the measurement periodlength which can be provided in the unicast/mixed frequency layer, theDRX cycle has a length which is equal to that of the measurement periodlength which can be set to a mobile terminal currently receiving an MBMSservice in the frequency layer dedicated to MBMS transmission, which isa minimum of the above-mentioned measurement period length, or which isan integral submultiple of the minimum of the above-mentionedmeasurement period length. As a result, even if any measurement periodlength is informed (set) to the mobile terminal from a unicast cell oran MBMS/Unicast-mixed cell, when the mobile terminal carries out ameasurement of the unicast/mixed frequency layer during a DRX periodwhich is provided in the DRX cycle in the frequency layer dedicated toMBMS transmission, the measurement period length informed from thenetwork side can be satisfied. By using this method, any control deviceof an MBMS transmission dedicated cell (a base station, an MCE, an MBMSgateway, an eBNSC, and so on) does not have to inform the DRX cyclelength and the DRX period length in the MBMS transmission dedicated cellto control devices of a unicast cell and an MBMS/Unicast-mixed cell.Therefore, there is provided an advantage of enabling a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBSFN transmission to carry out a measurement at measurement periods ofa length which a unicast cell or an MBMS/Unicast-mixed cell has informed(set) to the mobile terminal while preventing the mobile communicationsystem from becoming complicated, that is, avoiding addition ofsignaling onto a wireless interface or into the network. Furthermore,the mobile terminal can acquire broadcast information from a servingcell in the unicast/mixed frequency layer during the above-mentioned DRXperiod. For example, when the broadcast information in the serving cellis modified, the mobile terminal can deal with the modification. Theabove-mentioned determining method of determining a DRX period in afrequency layer dedicated to MBMS transmission, and the above-mentioneddetermining method of determining a DRX cycle in a frequency layerdedicated to MBMS transmission can also be used in the subsequentembodiments.

A concrete example of the parameters about the DRX information will beexplained with reference to FIG. 30. Concretely, as the parameters aboutthe DRX information, the DRX period length, the DRX cycle length, andthe starting point value (DRX) can be considered. Concretely, the numberof radio frames is used for the indication of each of the DRX periodlength and the DRX cycle length. In FIG. 30, the DRX period length is“4” radio frames (during a period between SFN 4 to SFN 7). Furthermore,the DRX cycle length is “7” radio frames (during a period between SFN 4to SFN 10). In addition, an SFN is used for the indication of thestarting point value (DRX) at which the DRX period starts. Somethingother than the number of radio frames can be used for the indication ofeach of the DRX period length and the DRX cycle length. As a concreteexample, the number of subframes can be used for the indication of eachof the DRX period length and the DRX cycle length. Something other thanan SFN can be used for the indication of the starting point value. As aconcrete example, an offset value from a certain reference value can beused for the indication of the starting point value. In a case in whichan MCCH is mapped onto some subframes in a radio frame, an SFN, asubframe number, and so on can be informed as the starting point. Aconcrete computation expression for calculating the starting point value(DRX) is given by (the starting point value (DRX)=(the SFN number of theleading system frame at which the DRX period starts) mod (the DRX cyclelength). In FIG. 30, the starting point value (DRX) is 4 mod 7=4, 11 mod7=4, or . . . . The example in which an SFN is used for the indicationof the starting point value (DRX) is shown above. Furthermore, in theexample, one DRX period is provided in the MBSFN synchronization area,as previously explained. Therefore, the starting point value (DRX) isalso common in base stations in the MBSFN synchronization area. A casein which an SFN is used as the starting point value (DRX) will beconsidered. It is assumed that the same number is transmitted from basestations in the MBSFN synchronization area at the same time. In theabove-mentioned example, the DRX information is mapped onto an MCCH andis transmitted from a base station in an MBSFN area to mobile terminals,as previously explained. Similarly, the DRX information can be mappedonto a BCCH and can be transmitted from a base station in an MBSFN areato mobile terminals. In this case, the same advantages are provided. Asan alternative, the DRX information can be mapped onto a BCCH and can betransmitted from a serving base station to mobile terminals. In thiscase, the same advantages are provided. Furthermore, even when the DRXinformation is determined statically (Static) or semi-statically(Semi-Static), the same advantages are provided. As a result, because itbecomes unnecessary to broadcast the DRX information, there can also beprovided an advantage of making effective use of the radio resources.

An example of the parameter for discontinuous reception at the time ofMBMS reception will be explained. As previously mentioned, nonpatentreference 1 discloses that a paging group is informed by using an L1/L2signaling channel (a PDCCH). Whether or not to make an L1/L2 signalingchannel exist in radio resources transmitted from an MBMS dedicated cellhas not been determined yet. In this embodiment, it is assumed that noL1/L2 signaling channel exists in radio resources transmitted from anMBMS dedicated cell. However, it is preferable that a paging informingmethod is unified as much as possible for a unicast cell, anMBMS/Unicast-mixed cell, and an MBMS transmission dedicated cell whichexist within the same mobile communication system which is called LTE.This is because by unifying a paging informing method, the mobilecommunication system can be prevented from becoming complicated. In thefollowing explanation, the number of paging groups (referred to asK_(MEMS) from here on) is considered as the parameter for discontinuousreception at the time of MBMS reception. Next, a case in which aplurality of base stations are arranged as shown in FIG. 25, and codedivision multiplexing of each MBSFN area is carried out as shown in FIG.27 will be explained. In this case, because the DRX information is thesame as that in the above-mentioned case in which time divisionmultiplexing of MBSFN areas is carried out, the explanation of the DRXinformation will be omitted.

Next, the “MBMS service selection”, which is described in Embodiment 1with reference to FIG. 19, will be explained more concretely. The mobileterminal, in step ST1730, checks the contents of a service included inthe MBMS area information in order to know whether or not a servicewhich the user desires is provided in a corresponding MBMS area. Thatis, the mobile terminal determines whether or not a desired service isprovided. When the service which the user desires is provided in theMBMS area in question, the mobile terminal makes a transition to stepST1731. In contrast, when the service which the user desires is notprovided in the corresponding MBMS area, the mobile terminal makes atransition to step ST1733. The mobile terminal, in step ST1731, receivesa reference signal (RS) with a radio resource of the MBSFN area inquestion, and measures the received power (RSRP) of the referencesignal. The mobile terminal then determines whether or not the receivedpower is equal to or higher than a threshold which is determinedstatically or semi-statically. The fact that the received power is equalto or higher than the above-mentioned threshold shows that the mobileterminal has high sensitivity enough to receive the MBMS service,whereas the fact that the received power is lower than the thresholdshows that the mobile terminal does not have high sensitivity enough toreceive the MBMS service. When the received power is equal to or higherthan the above-mentioned threshold, the mobile terminal makes atransition to step ST1732, whereas when the received power is lower thanthe above-mentioned threshold, the mobile terminal makes a transition tostep ST1733. The mobile terminal, in step ST1732, acquires a frequencyf(MBMS) dedicated to MBMS transmission and an MBSFN area ID which arerequired for the user to receive the desired MBMS service. On the otherhand, the mobile terminal, in step ST1733, determines whether or notanother MBMS area receivable within the same frequency band (f(MBMS))exists. This step ST1733 is effective particularly when an MBSFN area(an MBSFN area 4) covering other MBSFN areas as shown in FIG. 28 exists.When another MBMS area receivable within the same frequency band(f(MBMS)) exists, the mobile terminal returns to step ST1730 and repeatsthe process. In contrast, when any other MBMS area receivable within thesame frequency band (f(MBMS)) does not exist, the mobile terminal makesa transition to step ST1734. The mobile terminal, in step ST1734,determines whether or not another frequency exists in the frequency listof the receivable MBSFN synchronization area, which the mobile terminalreceives in step ST1708. When another frequency exists in the frequencylist, the mobile terminal returns to step ST1722 and switches itssynthesizer to the new frequency (f2(MBMS)), and then repeats theprocess. In contrast, when any other frequency does not exist in thefrequency list, the mobile terminal returns to step ST1720 and repeatsthe process. Instead of receiving the reference signal and measuring thereceived power in step 1731, the mobile terminal can actually receivethe MBMS service (an MTCH and/or an MCCH) in the MBSFN area in question.In this case, the user can determine whether the mobile terminalprovides receive sensitivity which he or she can permit by hearing orviewing decoded data. When the mobile terminal provides receivesensitivity which he or she can permit, the mobile terminal makes atransition to step ST1732, whereas when the mobile terminal does notprovide receive sensitivity which he or she can permit, the mobileterminal makes a transition to step ST1733. Because the permissiblereceive sensitivity has differences among individuals, there can beprovided an advantage of making mobile terminals be further suited forusers.

Step 1735 of FIG. 19 is a process of making “preparations fordiscontinuous reception at the time of MBMS reception” as described inEmbodiment 1. The mobile terminal, in step ST1735, makes preparationsfor discontinuous reception at the time of MBMS reception by using theparameter for discontinuous reception at the time of MBMS receptionwhich the mobile terminal receives in step ST1729. Concretely, themobile terminal determines the paging group of the mobile terminalitself by using the number K_(MBMS) of paging groups which the mobileterminal receives in step ST1729. The mobile terminal uses anidentification ID (UE-ID, IMSI) of the mobile terminal for thedetermination of the paging group. The paging group can be expressed asIMSI mod K_(MEMS).

FIG. 20 is a flow chart explaining a process of informing an MBMS sidereceiving state. This process will be a more-concretely explanation ofthe “notification of the MBMS side receiving state” described inEmbodiment 1 with reference to FIG. 17. In FIG. 20, the mobile terminal,in step ST1736, changes the frequency set to the frequency convertingunit 1107 thereof to change its center frequency to a frequency in theunicast/mixed frequency layer (referred to as f(unicast) from here on),so that the mobile terminal moves to the unicast/mixed frequency layer.The mobile terminal, in step ST1737, transmits an uplink schedulingrequest (a UL Scheduling Request) to a serving cell. The serving cell,in step ST1738, receives the uplink scheduling request from the mobileterminal. The serving cell, in step ST1739, carries out uplinkscheduling (UL Scheduling) so as to allocate an uplink radio resource tothe mobile terminal. The serving cell, in step ST1740, transmitsallocation of an uplink radio resource to the mobile terminal (referredto as UL allocation or Grant), which is the result of the uplinkscheduling in step ST1739, to the mobile terminal. The mobile terminal,in step ST1741, receives the UL allocation from the serving cell (i.e.,receives the allocation of an uplink radio resource). The mobileterminal, in step ST1742, transmits the “notification of the MBMS sidereceiving state” to the serving cell according to the UL allocationwhich the mobile terminal receives in step ST1741. As an example of theparameters included in the “notification of the MBMS side receivingstate”, an identifier (UE-ID, IMSI, S-TMSI, or the like) of the mobileterminal, the frequency (f(MBMS)) at which the mobile terminal receivesthe MBMS service, and the MBSFN area number (ID) are included.

Furthermore, the “notification of the MBMS receiving state” of stepST1742 can be made like in the case of an “attach request” shown inST1710, or as a type of “attach request”. As an alternative, the“notification of the MBMS receiving state” can be made like in the caseof “tracking area update (Tracking Area Update: TAU)”, or as a type of“tracking area update”. Parameters to be notified in this case includesan identifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal,the frequency (f(MBMS)) at which the mobile terminal receives the MBMSservice, and the MBSFN area number (ID), like in the above-mentionedcase. As a result, the network side is enabled to grasp the MBMSreceiving state of the mobile terminal in the MBMS dedicated cellwithout adding any new message. Therefore, there can be provided anadvantage of being able to avoid the complexity of the mobilecommunication system. Information showing that the “tracking areaupdate” includes the “notification of the MBMS receiving state” can beincluded in the “tracking area update”. As a concrete method, the“notification of the MBMS receiving state” can be added to the type(TYPE) information of TAU. The type information can be expressed as anumerical value. A 1-bit indicator showing whether or not to aim to makethe “notification of the MBMS receiving state” can be formed on the TAUrequest message. Information showing that the “attach request” messageincludes the “notification of the MBMS receiving state” can be includedin the “attach request” message. As a concrete method, the “notificationof the MBMS receiving state” can be added to the type information of theattach request. The type information can be expressed as a numericalvalue. A 1-bit indicator showing whether or not to aim to make the“notification of the MBMS receiving state” can be formed on the attachrequest message. As a result, in the former case, the conventional“tracking area update” can be distinguished from the “tracking areaupdate” used in order to inform the “MBMS receiving state”. Furthermore,in the latter case, the conventional “attach request” can bedistinguished from the “attach request” used in order to inform the“MBMS receiving state”. As a result, there can be provided an advantageof preventing a control delay time from occurring in the mobilecommunication system.

The serving cell, in step ST1743, carries out a receiving process ofreceiving the various parameters transmitted from the mobile terminalthrough the “MBMS receiving state notification” process of step ST1742.The network side, in step ST1743, can know that the mobile terminal inquestion is receiving the MBMS service in the frequency layer dedicatedto MBMS transmission without adding any uplink channel to the MBMSdedicated cell, i.e., without increasing the complexity of the mobilecommunication system. As a result, there is provided an advantage ofenabling the general configuration in which the network side informspaging signals to be changed into the configuration of carrying outdiscontinuous reception at the time of MBMS reception. The serving cell,in step ST1744, transmits the parameters transmitted thereto through the“notification of the MBMS receiving state” made by the mobile terminalin step ST1742 to an MME. The MME, in step ST1745, receives theseparameters.

The MME, in step ST1746, determines a tracking area (referred to as aTA(MBMS) from here on) in which the mobile terminal in question isreceiving the MBMS service at the frequency dedicated to MBMStransmission. The MME determines the tracking area on the basis of thenotification of the MBMS side receiving state (the parameters of theMBMS receiving state, f(MBMS), and the MBSFN area number) informed viathe serving cell from the mobile terminal in step ST1742. The MME, instep ST1747, updates the tracking area list of the mobile terminals inquestion. The MME, in step ST1747, carries out management (storage,addition, update, and deletion) of the TA list including a TA(unicast)and/or a TA(MBMS). The TA(unicast) is a tracking area of the mobileterminal in question in the unicast/mixed frequency layer. FIG. 31 is anexplanatory drawing explaining the details of the tracking area list.Hereafter, an example of the management of the tracking area list willbe explained with reference to FIG. 31. The tracking area list ismanaged for each mobile terminal as shown in FIG. 31(a). In the exampleof FIG. 31(a), a UE#1 has a TA(unicast) #1 and a TA(unicast) #2, and aUE#2 has a TA(unicast) #1 and a TA(MBMS) #1. The MME also manages basestations included in each tracking area (TA (unicast)). The managementof base stations will be explained with reference to FIG. 31(b).MBMS/Unicast-mixed cells having cell (Cell) IDs of 1, 2, 3, 4, and 5 areincluded in the TA(unicast) #1. MBMS/Unicast-mixed cells having cell IDsof 23, 24, and 25 are included in the TA(unicast) #2. Next, themanagement of base stations will be explained with reference to FIG.31(c). The TA(MBMS) #1 corresponds to the MBSFN area ID of the MBSFNarea in which the mobile terminal in question is receiving the MBMSservice in the frequency layer dedicated to MBMS transmission. Morespecifically, in accordance with the present invention, the mobileterminal, in step ST1742, transmits the parameters through the“notification of the MBMS side receiving state”, and the MME, in stepST1745, determines the TA(MBMS) by using f(MBMS) and the MBSFN area IDwhich are the parameters.

The details of the management of the TA list of step ST1747 will beexplained. The MME searches for the TA(MBMS) number which is managedwithin the MME on the basis of f(MBMS) and the MBSFN area ID which theMME receives in step ST1745 (for example, by using FIG. 31(c)). Next,the MME determines whether the TA(MBMS) which has been searched for asthe result of the search exists in the TA list of the mobile terminal inquestion. When the TA(MBMS) exists in the TA list, the MME stores thecurrent TA list. In contrast, when the TA(MBMS) does not exist in the TAlist, the MME adds the above-mentioned TA(MBMS) to the TA list of mobileterminal in question. The MME can manage (or register) multiple trackingareas (Multi-TA). The MME can also manage the TA(MBMS) and theTA(Unicast) as the multi-tracking area. The MME can separately managethe TA(MBMS) and the TA(Unicast), or can separately manage the trackingarea list for the TA(MBMS) and the tracking area list for the TA(Unicast). The MME, in step ST1748, transmits a response signal Ackshowing that the MME has received the notification of the MBMS sidereceiving state to the serving cell. It is possible to include the TAlist of the mobile terminal in question in this response signal. One ormore tracking areas (Multi-TA) can be included in the single TA list.The TA(MBMS) and the TA(Unicast) can be included in the single TA list.The TA list for the TA(MBMS) and the TA list for the TA(Unicast) can beseparately provided.

The serving cell, in step ST1749, receives the Ack to the notificationof the MBMS side receiving state from the MME, and, in step ST1750,transmits the Ack to the notification of the MBMS side receiving stateto the mobile terminal. The mobile terminal, in step ST1751, receivesthe Ack to the notification of the MBMS side receiving state from theserving cell. The mobile terminal, in step ST1752, moves to thefrequency layer dedicated to MBMS transmission by changing the frequencyset to the frequency converting unit 1107 thereof to change the centerfrequency to the frequency (f(MBMS)) in the frequency layer dedicated toMBMS transmission.

FIG. 21 is a flowchart showing a unicast side measurement process.Hereafter, the “unicast side measurement”, which is described inEmbodiment 1 with reference to FIG. 21, will be explained moreconcretely. The mobile terminal, in step ST1753, determines whether aDRX period start time of the MBMS service has come by using the DRXinformation which the mobile terminal receives in step ST1729 of FIG.19. As a concrete example, the mobile terminal determines the SFN numberof the leading system frame at which a DRX period starts by using theDRX cycle length and the starting point value (DRX) which are an exampleof the parameters which the mobile terminal receives in step ST1729, anddetermines whether or not a DRX period start time has come on the basisof the SFN mapped onto the BCCH (broadcast control channel) or the like.A concrete example of the computation is expressed as SFN=the DRX cyclelength×α+the starting point value (DRX), where α is a positive integer.When no DRX period start time has come yet, the mobile terminal makes atransition to step ST1772. In contrast, when a DRX period start time hascome, the mobile terminal makes a transition to step ST1754. The mobileterminal, in step ST1754, determines whether or not the DRX period starttime is in a measurement period in the MBMS/Unicast-mixed cell receivedin step ST1705. When the DRX period start time is not in a measurementperiod, the mobile terminal makes a transition to step ST1772. Incontrast, when the DRX period start time is in a measurement period, themobile terminal makes a transition to step ST1755. The mobile terminal,in step ST1755, receives a downlink signal of the MBMS/Unicast-mixedcell by changing the frequency set to the frequency converting unit 1107thereof (the synthesizer) to change the center frequency to f (Unicast).The mobile terminal, in step ST1756, carries out a measurement on theside of the unicast (i.e., a measurement of a unicast cell and/or anMBMS/Unicast-mixed cell). As values which the mobile terminal actuallymeasures, the RSRPs, RSSIs, etc. of the serving cell and a neighboringcell can be considered. The information about the neighboring cell canbe broadcast, as neighboring cell information (a list), from the servingcell.

The mobile terminal, in step ST1757, judges whether or not are-selection (a cell re-selection) of the serving cell is neededaccording to the result of the measurement in step ST1756. As an exampleof a criterion of the judgment, there can be considered whether theresult of the measurement of one cell among neighboring cells exceedsthe result of the measurement of the serving cell. When no re-selectionis needed, the mobile terminal makes a transition to step ST1771. Incontrast, when a re-selection is needed, steps ST1758 and ST1759 arecarried out. Abase station (a new serving cell: New serving cell) whichis newly selected as the serving cell in step 1758 broadcasts themeasurement period length, the discontinuous reception cycle length, andthe tracking area information (the TA information) to mobile terminalsbeing served thereby by using the BCCH (broadcast control channel), likein the case of step ST1705. The mobile terminal, in step ST1759,receives and decodes the BCCH from the new serving cell to receive themeasurement period length, the discontinuous reception cycle length, andthe TA information. The mobile terminal, in step ST1760, checks to seewhether or not the TA information of the serving base station receivedin step ST1759 is included in the current tracking area list (TA List)which is stored in the protocol processing unit 1101 or the control unit1110 thereof. When the TA information is included in the currenttracking area list, the mobile terminal makes a transition to stepST1771. In contrast, when the TA information is not included in thecurrent tracking area list, the mobile terminal performs step ST1761. Anexplanation of steps ST1761 to ST1770 will be omitted because it is thesame as that of steps ST1710 to ST1719. The mobile terminal, in stepST1771, moves to the frequency layer dedicated to MBMS transmission bychanging the frequency set to the frequency converting unit 1107 thereofto change the center frequency to f(MBMS).

Through the “unicast side measurement” process in steps ST1753 toST1771, the mobile terminal can carry out a measurement of a unicastcell and/or an MBMS/Unicast-mixed cell even if the mobile terminal isreceiving an MBMS service in the frequency layer dedicated to MBMStransmission. Accordingly, there is provided an advantage of making itpossible for a mobile terminal currently receiving an MBMS service in afrequency layer dedicated to MBMS transmission to ensure the mobility inunicast cells and/or MBMS/Unicast-mixed cells. As a result, there can beprovided an advantage of becoming able to ensure the mobility in MBMSdedicated cells in which no uplink channel exists by way of anMBMS/Unicast-mixed cell. Therefore, there is provided an advantage ofenabling even a mobile terminal currently receiving an MBMS service in afrequency layer dedicated to MBMS transmission to receive a pagingsignal. Furthermore, a mobile terminal currently receiving a service ina frequency layer dedicated to MBSFN transmission carries out downlinksynchronization establishment with a unicast cell or anMBMS/Unicast-mixed cell through a measurement at measurement periods. Asa result, there can be provided an advantage of enabling a mobileterminal which has received a paging signal in a frequency layerdedicated to MBMS transmission in which no uplink channel exists toimplement even transmission of a response to the paging signal in aunicast cell or an MBMS/Unicast-mixed cell with a short control delaytime, which is presented as a challenge of the present invention.

FIG. 22 is a flow chart showing the discontinuous reception process atthe time of MBMS reception, and explains the “discontinuous reception atthe time of MBMS reception” which is described in Embodiment 1 withreference to FIG. 17 more concretely. The mobile terminal, in stepST1772 of FIG. 21, determines whether the current time is a time ofreceiving the MCCH of the number of the MBSFN area from which the mobileterminal is receiving an MBMS from the MCCH scheduling information ofthe MBMS area information. That is, the mobile terminal determineswhether the current time is a time of receiving the MCCH by using thescheduling of the MCCH (multicast control channel) received in stepST1725. More specifically, the mobile terminal determines the SFN numberof the leading one of system frames onto which the MCCH is mapped byusing the MCCH repetition period length and the starting point valuewhich are examples of the parameters which the mobile terminal receivesin step ST1725, and determines whether or not it is the leading one ofsystem frames onto which the MCCH is mapped on the basis of an SFNmapped onto the BCCH or the like to determine whether it is the SFNnumber of the leading one of system frames onto which the MCCH ismapped. When the current time is not the one of the leading one ofsystem frames onto which the MCCH is mapped, the mobile terminal makes atransition to step ST1753. In contrast, when the current time is the oneof the leading one of system frames onto which the MCCH is mapped, themobile terminal makes a transition to step ST1784. As an alternative, ina case of FIG. 26, for example, the determination of step ST1772 can becarried out every MCCH repetition period 1.

In step ST1772, the time of receiving the MCCH (the SFN number of theleading one of system frames onto which the MCCH is mapped), and thediscontinuous reception cycle length at the time of MBMS reception canbe different. By making them different, it becomes able to “lengthen” or“shorten” the discontinuous reception cycle length at the time of MBMSreception according to the network conditions or the like, and themobile communication system can be configured in such a way as to havehigher flexibility. In step ST1707, the discontinuous reception cyclelength at the time of MBMS reception can be mapped onto the BCCH andinformed from the serving cell to the mobile terminal. As analternative, in step ST1723, the discontinuous reception cycle length atthe time of MBMS reception can be mapped onto the BCCH, and informedfrom the MBMS dedicated cell to the mobile terminal. As an alternative,in step ST1728, the discontinuous reception cycle length at the time ofMBMS reception can be mapped onto the MCCH, and informed from the MBMSdedicated cell to the mobile terminal. More specifically, the mobileterminal determines whether or not the current time is a discontinuousreception timing at the time of MBMS reception in step ST1772, and, whenthe current time is a discontinuous reception timing, makes a transitionto step 1784. In contrast, when the current time is not a discontinuousreception timing, the mobile terminal determines whether or not thecurrent time is a receiving one of receiving the MCCH, and, when thecurrent time is a receiving one of receiving the MCCH, the mobileterminal makes a transition to step ST1788. In contrast, when thecurrent time is not a receiving one of receiving the MCCH, the mobileterminal makes a transition to step ST1753 of FIG. 21.

When, in step ST1773, paging to the mobile terminal in question occurs,the MME, in step ST1774, checks the tracking area (TA) list of themobile terminal in question on the basis of an identifier (UE-ID, IMSI,S-TMSI, or the like) of the mobile terminal which is the destination ofthe paging. The MME, in step ST1775, determines whether or not theTA(MBMS) is included in the tracking area list of the mobile terminal inquestion. As an example, the MME searches through the tracking area listof the mobile terminal in question, such a list as shown in FIG. 31(a),on the basis of the UE-ID. In a case in which the mobile terminal inquestion is the UE#1 (UE-ID#1) of FIG. 31(a), the MME determines thatthe TA(MBMS) is not included is the tracking area list. In contrast, ina case in which the mobile terminal in question is the UE#2 (UE-ID#2) ofFIG. 31(a), the MME determines that the TA(MBMS) is included is thetracking area list because the TA(MBMS)#1 is included in the list. Whenthe TA(MBMS) is not included in the tracking area list, the MME makes atransition to step ST1814. In contrast, when the TA(MBMS) is included inthe tracking area list, the MME makes a transition to step ST1776. TheMME, in step ST1776, transmits a paging request (Paging Request) toMCEs. More specifically, the MME 103 of FIG. 10 transmits a pagingrequest to MCEs 801 by using interfaces between MME and MCE. As the MCEsto which the MME transmits a paging request, there can be considered allMCEs each of which manages base stations which geographically overlapthe base stations managed by the MME.

As an example of parameters included in the paging request, there can beconsidered an identifier (UE-ID, IMSI, S-TMSI, or the like) of themobile terminal, the TA(MBMS) number, and so on. At this time, insteadof the TA(MBMS) number, both f(MBMS) and the MBSFN area ID or only theMBSFN area ID can be provided. Each of the MCEs, in step ST1777,receives the paging request. Among the MCEs each of which receives thepaging request in step ST1778, an MCE which controls the MBSFN area IDwhich is informed thereto as a parameter included in the paging request,and which is related to the TA(MBMS) number makes preparations forpaging transmission. In contrast, an MCE which does not control theMBSFN area ID related to the TA(MBMS) number does not make preparationsfor paging transmission. As an example of the preparations for pagingtransmission, an MCE which controls the MBSFN area ID determines thepaging group of the mobile terminal in question by using both the numberK_(MBMS) of paging groups of the base stations managed thereby (theMBSFN area to which the base stations belong), and the received pagingrequest. When determining the paging group, the MCE uses the samecomputation expression as that used by the mobile terminal (Paginggroup=IMSI mod K_(MBMS)). As mentioned above, because the method ofmanaging the correspondence between the TA(MBMS) number (the MBSFN area)and MCEs, which each MCE receiving the paging request uses, enables arelationship between the MBSFN area ID and MCEs each of which controlsthe MBSFN area to be built within only the architecture of the MBMSservice, that is, because the method can be implemented regardless ofthe MME, there can be provided an advantage of being able to configurethe mobile communication system in such a way as to have highflexibility.

Furthermore, there is considered a case in which the MME manages theMBSFN area ID related to the TA(MBMS) number as shown in FIG. 31(c), andalso manages the MBSFN area ID and the number of an MCE which controlsthe MBSFN area as shown in FIG. 31(d). In this case, the MME, in stepST1776, transmits the paging request only to an MCE which manages theMBSFN area ID related to the TA(MBMS) number. As an example of aparameter included in the paging request at that time, there can beconsidered an identifier of the mobile terminal, or the like. The MCEwhich receives the paging request in step ST1778 makes preparations forpaging transmission, like in the above-mentioned case. As mentionedabove, because the method (FIG. 31(d)) of managing the relationshipbetween an MBSFN area ID and an MCE which controls the MBSFN area in theMME reduces the number of MCEs to which the paging request istransmitted from the MME, there is provided an advantage of being ableto make effective use of the resources. Furthermore, because the amountof information to be informed decreases, there is provided an advantageof being able to make effective use of the resources.

Furthermore, there is considered a case in which the MME manages theMBSFN area ID related to the TA(MBMS) number as shown in FIG. 31(c), andalso manages the MBSFN area ID and the cell IDs of the MBMS dedicatedcell and/or the MBMS/Unicast-mixed cell which is included in the MBSFNarea ID as shown in FIG. 31(e). In this case, the MME, in step ST1776,transmits the paging request to the cells whose IDs are included inMBSFN area ID which is not managed by an MCE but by the MME. A newinterface is disposed between the MME and each MBMS dedicated cell. TheMME transmits the above-mentioned paging request to each MBMS dedicatedcell included in the MBSFN area having the MBSFN area ID by using thenew interface. As an example of a parameter included in the pagingrequest at that time, there can be considered an identifier of themobile terminal, or the like. As mentioned above, the method of managingthe relationship between an MBSFN area ID and cells whose IDs areaincluded in the MBSFN area ID in the MME (FIG. 31(e)) eliminates thenecessity for an MCE to carry out processes regarding the transmissionof a paging signal to the mobile terminal. Because this results inelimination of the necessity to add any function to each MCE, there canbe provided an advantage of being able to avoid the complexity of eachMCE. Furthermore, there can be provided an advantage of being able toreduction the processing load on each MCE.

FIG. 32 is an explanatory drawing explaining an example of the structureof a channel onto which a paging signal in a frequency layer dedicatedto MBMS transmission is mapped. FIG. 32(a) is a view showing aconfiguration including MBMS-related information and a paging signal ona PMCH (Physical multicast channel). The MBMS-related information ismapped onto logical channels MTCH and MCCH for MBMS. The MBMS-relatedinformation and the paging signal can exist as information elements inthe MTCH and the MCCH respectively, or time-division multiplexing ofphysical areas (resources) onto which the MBMS-related information andthe paging signal are mapped respectively can be carried out. Each ofall cells in an MBSFN area carries out multi-cell transmission of anMCCH periodically in this MBSFN area by using a PMCH corresponding tothe MBSFN area. On the other hand, a mobile terminal which is receivingor trying to receive an MBMS service transmitted via a multi-celltransmission scheme from cells in the above-mentioned MBSFN areareceives the above-mentioned MCCH at regular intervals and also receivesthe contents of the MBMS service, information about the frame structure,etc., so that the mobile terminal can receive the MBMS service.

By including the paging signal in this MCCH, a mobile terminal which isreceiving or trying to receive an MBMS service is enabled to receive thepaging information when receiving the MCCH. As a result, because themobile terminal does not have to receive the paging separately at a timeother than the time of receiving the MCCH, the mobile terminal canreceive the paging without interrupting the reception of the MBMSservice. Furthermore, during a time period during which the mobileterminal is not receiving the MCCH, and during a time period duringwhich the mobile terminal is not receiving the MBMS service, the mobileterminal can carry out a DRX operation (discontinue the receivingoperation), thereby reducing its power consumption. Furthermore, theMCCH and the PCCH onto which the paging signal is mapped can beconfigured in the same MBSFN subframes, and an MBSFN subframe onto whichthe MCCH is mapped and an MBSFN subframe on which the paging signal ismapped can be arranged in such a way as to be adjacent to each other intime. In the case in which they are configured in this way, a mobileterminal which is receiving or trying to receive an MBMS service isenabled to receive the paging signal continuously when receiving theMCCH. As a result, because the mobile terminal does not have to carryout any reception for the reception of the paging at a time other thanthe time of receiving continuous MBSFN subframes onto which the MCCH andthe paging signal are mapped, the mobile terminal can receive the pagingsignal without interrupting the reception of the MBMS service.Furthermore, during a time period during which the mobile terminal isnot receiving the MCCH and the paging signal, and during a time periodduring which the mobile terminal is not receiving the MBMS service, themobile terminal can carry out a DRX operation, thereby reducing itspower consumption.

A configuration of disposing an indicator indicating whether or not theMBMS control information has been changed, and an indicator indicatingwhether or not the paging signal has been transmitted is disclosed inFIG. 32(b). In FIG. 32(b), the indicator 1 indicates whether the pagingsignal has been transmitted, and is referred to as the paging signalpresence or absence indicator. The indicator 2 indicates whether or notthe MBMS control information has been changed, and is referred to as theMBMS-related information modified or unmodified indicator. A physicalarea onto which each of the indicators is mapped can be disposed in anMBSFN subframe via which the PMCH is transmitted. As an alternative, aphysical area onto which each of the indicators is mapped can be the oneadjacent in time to an MBSFN subframe via which the PMCH is transmitted.By configuring the physical area onto which each of the indicators ismapped in this way, the mobile terminal can receive and decode the MCCHwhich is mapped onto the PMCH and the paging signal immediately afterreceiving the indicators. Concretely, 1-bit (bit) information is definedas each of the indicators. Each of the indicators is multiplied by anMBSFN-area-specific scrambling code or the like, and is mapped onto apredetermined physical area. As an alternative method, for example, eachof the indicators can be formed of an MBSFN-area-specific sequence, andcan be mapped onto a predetermined physical area. When an incoming callto the mobile terminal is occurring, the paging signal presence orabsence indicator is set to “1”, for example, whereas when no incomingcall thereto is occurring, the mobile terminal sets the paging signalpresence or absence indicator to “0”. Furthermore, for example, when theMBMS control information which is mapped onto the MCCH has been changeddue to change in the contents of the MBMS service transmitted in theMBSFN area, or the like, the mobile terminal sets the MBMS-relatedinformation modified or unmodified indicator to “1”, for example. Themobile terminal determines the length of a time period (referred to asan MBMS modification period) during which the MBMS-related informationincluding the MBMS control information and the MBMS-related informationmodified or unmodified indicator can be modified one or more times, andthe base station repeatedly transmits the MBMS-related informationmodified or unmodified indicator “1” within this time period. The lengthof the MBMS modification period, the start timing (the SFN and thestarting point), etc. can be predetermined. As an alternative, they canbe informed via broadcast information from either a serving cell forunicast service or an MBMS dedicated cell. When there is no furthermodification in the MBMS-related information after the expiration of theMBMS modification period, the mobile terminal sets the MBMS-relatedinformation modified or unmodified indicator to “0”, for example. Themobile terminal can determine whether or not there is a modification inthe MBMS-related information which exists in the MCCH and whether or notthe paging signal exists by receiving the indicators in the MCCH of adesired MBSFN area, and performing de-spreading and so on each of theindicators to determine whether or not each of the indicators is 1 or 0.

By thus disposing each of the indicators, when there is no modificationin the MBMS control information and when no paging signal exists, themobile terminal does not have to receive and/or decode all theinformation on the PMCH. Therefore, it becomes able to reduce the powerfor receiving of the mobile terminal. By further determining the lengthof the time period during which the MBMS-related information can bemodified, and enabling identical MBMS control information to betransmitted one or more times within a single time period having thelength, the mobile terminal becomes able to receive the identical MBMScontrol information one or more times. Therefore, the error rate ofreception of the MBMS control information can be reduced, and thequality of reception of the MBMS service can be improved. The physicalarea onto which the MBMS-related information modified or unmodifiedindicator indicating whether the MBMS control information has beenmodified is mapped can be the first one of one or more MBSFN subframesonto which the MBMS control information is mapped. As an alternative,the physical area onto which the MBMS-related information modified orunmodified indicator indicating whether the MBMS control information hasbeen modified is mapped can be a first OFDM symbol of theabove-mentioned first MBSFN subframe. As a result, the mobile terminalbecomes able to determine whether a modification has occurred in theMBMS control information by receiving the first OFDM symbol.

Furthermore, the physical area onto which the paging signal presence orabsence indicator indicating whether or not the paging signal exists ismapped can be the first one of one or more MBSFN subframes onto whichthe paging signal is mapped. As an alternative, the physical area ontowhich the paging signal presence or absence indicator indicating whetheror not the paging signal exists is mapped can be an OFDM symbol at thehead of the above-mentioned first MBSFN subframe. As a result, themobile terminal becomes able to determine whether or not the pagingsignal exists by receiving the first OFDM symbol. By mapping eachindicator onto such a physical area as mentioned above, when there is nomodification in the MBMS control information and when no paging signalexists, the mobile terminal does not have to receive and/or decodesubsequent OFDM symbols. Therefore, it becomes able to further reducethe power for receiving of the mobile terminal. Furthermore, because themobile terminal can determine whether there is no modification in theMBMS control information or whether a paging signal exists at an earliertime from the first MBSFN subframe or the OFDM symbol at the head of thefirst MBSFN subframe, the mobile terminal can receive the MBMS controlinformation immediately or can receive the paging signal immediately, itbecomes able to reduce the control delay in the mobile terminal.

The MBMS-related information modified or unmodified indicator and thepaging signal presence or absence indicator can be mapped onto anidentical physical area, or can be mapped onto different physical areas.In a case in which the indicators are mapped onto an identical physicalarea, what is necessary is just to implement an OR logical operation onthe indicators. As a result, the mobile terminal has only to receive asingle indicator, there is provided an advantage of being able tosimplify the receiving circuit configuration. In contrast, in a case inwhich the indicators are mapped onto different physical areas, themobile terminal has only to receive only a required one of theindicators without having to receive the other indicator. Therefore, thepower for receiving of the mobile terminal can be further reduced, andthe delay occurring in the reception of the required information can befurther reduced. For example, a mobile terminal which is set so as notto receive a paging signal while receiving an MBMS service has only toreceive the MBMS-related information modified or unmodified indicator,and can eliminate the necessity to receive the paging signal presence orabsence indicator. Furthermore, in the case in which the MBMS-relatedinformation modified or unmodified indicator and the paging signalpresence or absence indicator are mapped onto different physical areas,when, in step ST1772, the receiving time of receiving the MCCH (the SFNnumber of the leading one of system frames onto which the MCCH ismapped) or the length of an MBMS-related modified or unmodifiedindicator repetition period, and the length of a paging signal presenceor absence indicator repetition period are set to different values, themobile terminal can receive and/or decode only the MBMS-relatedinformation modified or unmodified indicator at the MCCH receiving timeor during an MBMS-related modified or unmodified indicator repetitionperiod, and can receive and/or decode the paging signal presence orabsence indicator during a paging signal presence or absence indicatorrepetition period. As a result, there can be provided an advantage ofreducing the processing time of the mobile terminal and being able toestablish low power consumption in the mobile terminal.

The lengths of the repetition periods of the indicators can be the sameas each other, or can be different from each other. The length of therepetition period of each of the indicators can be the same as that ofthe MCCH, or can be different from that of the MCCH. For example, thelength of the repetition period of the MBMS-related information modifiedor unmodified indicator is set to be the same as the length of therepetition period of the MCCH (the length of the MCCH RepetitionPeriod), and the length of the repetition period of the paging signalpresence or absence indicator is set to be n times as long as the lengthof the repetition period of the MCCH (n is an integer greater than orequal to 2). By thus setting the repetition period lengths, it becomesable to “lengthen” or “shorten” the discontinuous reception cycle lengthat the time of MBMS reception according to the network conditions or thelike, and the mobile communication system can be configured in such away as to have higher flexibility. The lengths of the repetition periodsof the indicators are referred to as the paging signal presence orabsence indicator repetition period (Repetition period) and theMBMS-related modified or unmodified indicator repetition period(Repetition period). The start timing (the SFN and the starting point)of the MBSFN subframe in which the indicator exists, the subframenumber, the repetition period lengths of the indicators, and so on canbe informed via broadcast information from a serving cell for unicastservice, can be informed via broadcast information from an MBMSdedicated cell, or can be predetermined. In this case, the mobileterminal carries out step ST1772, ST1788, or ST1789 during eachMBMS-related modified or unmodified indicator repetition period. Achannel dedicated to the MBMS-related information modified or unmodifiedindicator can be an MICH (MBMS Indicating CHannel), for example.Furthermore, the paging signal presence or absence indicator can beformed in the MICH. The length of the repetition periods at which theMICH is repeated is referred to as the “MICH repetition period” (MICHRepetition period). The repetition period length of the paging signalpresence or absence indicator can be the same as that of the MICH, orcan be different from that of the MICH. The notification of theindicators can be made by using the same method as that describedpreviously. In this case, the mobile terminal carries out step ST1772 orST1784 during each paging signal presence or absence indicatorrepetition period. As a result, the time when each indicator istransmitted is not limited to the time when the MCCH is transmitted, andtherefore it becomes able to flexibly design the system.

In a case in which the paging signal is included in the PMCH, therearises a problem that when the number of mobile terminals for each ofwhich an incoming call is occurring becomes huge, it takes too much timefor each mobile terminal to detect a paging signal destined for themobile terminal itself. A further problem is that any area onto whichthe paging signals for all the mobile terminals for each of which anincoming call is occurring are to be mapped cannot be ensured in acertain physical area onto which the paging signals are to be mapped. Inorder to solve these problems, a method of carrying out paging groupingwill be disclosed hereafter. The method of carrying out paging groupingis shown in FIG. 32(c). All mobile terminals are divided into K groups,and a paging signal presence or absence indicator is disposed for eachof the groups. The physical area used for the paging signal presence orabsence indicator in the MCCH is divided into K parts, and the pagingsignal presence or absence indicators of the K groups are mapped ontothe K divided parts of the physical area respectively. In this case, Kcan have a value ranging from 1 to the number of all the mobileterminals. When an incoming call to a mobile terminal is occurring, thepaging signal presence or absence indicator of the group to which thismobile terminal belongs is set to “1”. When no incoming call to any ofall the mobile terminals belonging to a group is occurring, the pagingsignal presence or absence indicator of this group is set to “0”.Repetition or the like of the paging signal presence or absenceindicator value can be carried out so that each of the mobile terminalssatisfies a desired error rate of reception. The physical area ontowhich paging signals are mapped is also divided into K parts, and theseK parts are brought into correspondence with the above-mentioned Kgroups respectively. As a paging signal destined for each mobileterminal, an identifier of the mobile terminal (an identification numberor an identification code) can be provided. Each of the K divided piecesof the physical area is the sum of the corresponding group's mobileterminals' physical areas in each of which paging signal data requiredby one mobile terminal is accommodated. The number of mobile terminalsin each group can be identical to that in any other group, or can bedifferent from that in any other group.

The number of mobile terminals in each group is calculated by using, forexample, a method of calculating the average of the number of mobileterminals for each of which an incoming call has occurredsimultaneously. As an alternative, a method of defining the number ofmobile terminals which can be allocated to one OFDM symbol in the entirefrequency band as the number of mobile terminals in each group, and thenbringing a plurality of OFDM symbols into correspondence with theplurality of groups respectively can be used. When an incoming call to amobile terminal is occurring, “1” is set to the paging signal presenceor absence indicator of the group to which this mobile terminal belongs,and the paging signal presence or absence indicator is mapped onto thephysical area corresponding to this group and used for the paging signalpresence or absence indicator. In addition, the paging signal destinedfor the mobile terminal for which an incoming call is occurring ismapped onto the physical area of the paging signal corresponding to thegroup to which this mobile terminal belongs. The mapping of the pagingsignal to the physical area is carried out by using a method ofmultiplying the paging signal destined for each mobile terminal by anidentification code specific to the mobile terminal. The paging signaldestined for each mobile terminal can be an identifier of the mobileterminal. In this case, the control operation of multiplying the pagingsignal destined for each mobile terminal by the above-mentionedidentification code specific to the mobile terminal can be omitted. Eachmobile terminal determines whether an incoming call destined for thegroup to which the mobile terminal itself belongs is occurring byreceiving the paging signal presence or absence indicator of the groupto which the mobile terminal itself belongs. When determining that anincoming call is occurring, each mobile terminal receives and decodesthe physical area onto which the paging signal brought intocorrespondence with the group onto which the mobile terminal belongs ismapped. After decoding the physical area, each mobile terminal carriesout an operation of calculating a correlation with the identificationcode specific to the mobile terminal to carry out blind detection tospecify the paging signal destined for the mobile terminal itself. As aresult, each mobile terminal becomes able to determine that an incomingcall to the mobile terminal itself is occurring. When each mobileterminal has not detected the paging signal destined therefor, themobile terminal itself determines that no incoming call thereto isoccurring.

By grouping all the mobile terminals into the K groups, the necessityfor each of the mobile terminals to receive all of the area dedicated topaging signals can be eliminated, and each of the mobile terminals hasonly to receive only a required area, i.e., a physical areacorresponding to the group to which the mobile terminal itself belongs.Therefore, the length of time required for each of the mobile terminalsto detect the paging signal destined therefor can be shortened.Furthermore, because each of the mobile terminals does not have toreceive a physical area corresponding to any other group to which themobile terminal itself does not belong, the power for receiving of eachof the mobile terminals can be reduced. In addition, by using the pagingsignal presence or absence indicator corresponding to each group, alsowhen there are many mobile terminals, the paging signal presence orabsence indicators can be provided with a small amount of physicalresources. Furthermore, each of the mobile terminals has only to receivean area dedicated to paging signals as needed. Therefore, while thepower for receiving of each of the mobile terminals can be reduced, thecontrol delay can also be reduced because each of the mobile terminalscan make a transition to the next operation immediately when it does nothave to receive the paging signal.

In above-mentioned Embodiment, each of the K divided pieces of thephysical area onto which paging signals are mapped is the sum of thecorresponding group's mobile terminals' physical areas in each of whichpaging signal data required by one mobile terminal is accommodated.However, because the required physical area becomes very large and theoverhead for transmitting the MBMS service increases greatly as thenumber of mobile terminals becomes huge, the transmission rate of theMBMS service data decreases. In order to prevent this problem, thepaging signal destined for each of the mobile terminals is multiplied byan identification code specific to the mobile terminal itself. As aresult, because each of the mobile terminals becomes able to carry outblind detection (Blind Detection) of whether or not it is informationdestined for the mobile terminal itself by using the identification codespecific to the mobile terminal, it becomes unnecessary to fix thephysical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, there is no necessityto provide a physical area used for the paging signals destined for allthe mobile terminals, and a physical area which is large enough to mappaging signals destined for a certain number of mobile terminals foreach of which an incoming call is predicted to actually occur has onlyto be provided. As an example, there is a method of defining the averageof the number of mobile terminals for each of which an incoming call hasoccurred simultaneously as the number of mobile terminals to be includedin each group. By using this method, it becomes able to use the limitedamount of physical resources effectively. Furthermore, by using theabove-mentioned method, the mobile communication system can flexiblydeal with even a case in which the number of mobile terminals for eachof which an incoming call is occurring becomes larger than a predictednumber through scheduling in a base station. For example, the mobilecommunication system can transmit a paging signal destined for a mobileterminal receiving a new incoming call on the next PMCH.

When the number of all the mobile terminals is small, only the pagingsignal presence or absence indicators can be transmitted by setting thevalue of K to be equal to the number of the all mobile terminals. Inthis case, there is no necessity to ensure the paging-related physicalarea, and what is necessary is just to ensure a physical area used forthe paging signal presence or absence indicators and corresponding tothe number of all the mobile terminals. Therefore, the efficiency of theradio resources can be improved. Furthermore, in this case, there existsa physical area used for a paging signal presence or absence indicatorand corresponding to each mobile terminal. Therefore, each of the mobileterminals can determine the presence or absence of an incoming callwithout receiving the area for paging signals by simply receiving anddecoding the physical area used for a paging signal presence or absenceindicator and corresponding to the mobile terminal itself, thereby beingable to reduce the control delay occurring when performing the pagingoperation.

An example of the method of mapping paging signals onto a physical areaon the PMCH onto which the paging signals are to be mapped is shown inFIG. 33. Paging signals destined for mobile terminals n1, n2, and so onfor each of which an incoming call is occurring, among mobile terminals(shown by A in FIG. 33) belonging to a paging group n, are mapped onto aphysical area corresponding to this group n. Abase station multipliesthe paging signal destined for each of the mobile terminals by anidentification code specific to this mobile terminal (a number or asequence) (process 1), carries out CRC addition (process 2), and carriesout a process including encoding and rate matching (process 3). When thepaging signal destined for each of the mobile terminals is an identifierof the mobile terminal, the control operation of multiplying the pagingsignal by the above-mentioned mobile-terminal-specific identificationcode can be omitted. The result of the series of processes carried outis allocated to an information element unit having a size correspondingto the size of the physical area onto which the paging signal is to bemapped (process 4), and a plurality of information element units whosenumber is equal to that of the mobile terminals for each of which anincoming call is occurring are connected to one another. The connectedresult is subjected to a scrambling process using an MBSFN-area-specificscrambling code, a modulation process, etc. (process 5). The modulationprocess can be specific to the MBSFN area. The result of carrying outthese processes is mapped onto the physical area corresponding to thepaging group n (process 6). In this case, the base station sets “1” tothe paging signal presence or absence indicator (indicator 1) of thepaging group n, and then maps it onto the physical area corresponding tothe paging group n of the paging signal presence or absence indicator.The physical area corresponding to the paging group n can bepredetermined, or can be informed, as broadcast information, from eithera unicast side serving cell or an MBMS dedicated cell to the basestation. Each of the mobile terminals receives the paging signalpresence or absence indicator of the paging group to which the mobileterminal itself belongs, and, when the paging signal presence or absenceindicator has a value of “1”, receives the physical area for pagingsignal corresponding to this paging group. Each of the mobile terminalsreceives the physical area for paging signal, carries out demodulationand descrambling using the MBSFN-area-specific scrambling code, anddivides the result of the demodulation and descrambling into parts eachcorresponding to an information element unit. Each of the mobileterminals carries out blind detection of the paging signal destined forthe mobile terminal itself by performing a process including decoding oneach of the divided parts each corresponding to an information elementunit, and then carrying out a correlation operation with themobile-terminal-specific identification number. When the result of thecorrelation operation is larger than a certain threshold, each of themobile terminals determines that there is paging destined for the mobileterminal itself, and starts an operation of receiving a paging incomingcall with the paging signal. In contrast, when the result of thecorrelation operation is equal to or smaller than the certain threshold,each of the mobile terminals determines that there is no paging destinedfor the mobile terminal itself, and makes a transition to reception ofMBMS-related information or makes a transition to a DRX operation ifthere is no necessity to receive any MBMS-related information. To whichgroup each of the mobile terminals belongs can be determined by using apredetermined determining method, or can be informed, as broadcastinformation, from either a serving cell for unicast service or an MBMSdedicated cell to the mobile terminal via an upper layer.

In the above-mentioned example, the paging signal destined for each ofthe mobile terminals is allocated to a control information element unithaving a size corresponding to the size of the physical area onto whichthe paging signal is to be mapped. As an alternative, the paging signaldestined for each of the mobile terminals can be allocated to atransport block unit. In the case in which the paging signal destinedfor each of the mobile terminals is allocated to a transport block unit,the physical resource to which the paging signal is allocated can beincreased or decreased according to the amount of information, and theallocation to the physical area can be carried out with flexibility.

Furthermore, in the above-mentioned example, the base station carriesout the process 1 of multiplying the paging signal destined for each ofthe mobile terminals by an identification code specific to this mobileterminal. The base station can alternatively use another processingmethod of adding the paging signal destined for each of the mobileterminals and an identification number specific to this mobile terminal.In this case, each of the mobile terminals receives the physical areafor paging signal, carries out demodulation and descrambling using anMBSFN-area-specific scrambling code, and divides the result of thedemodulation and descrambling into parts each corresponding to aninformation element unit, and performs a process including decoding oneach of the divided parts each corresponding to an information elementunit. Each of the mobile terminals then determines whether theidentification number specific to the mobile terminal itself exists inthe information on which the mobile terminal itself has performed theprocess including decoding to detect the paging signal destinedtherefor.

Furthermore, when mapping the paging signals onto the PMCH, in order todistinguish this PMCH from other information, e.g., an MCCH and an MTCH,the base station can multiply each of them by a specific identifier (ID)different according its information type. Because an identifier specificto each information type is used in MBSFN subframes which aretransmitted via a multi-cell transmission scheme, unlike in the case ofunicast communications, it is necessary to transmit an identicalspecific identifier from a plurality of cells each of which carries outmulti-cell transmission. For example, an identifier specific to eachidentical information type is used in each MBSFN area. As an example, anMBMS dedicated cell multiplies paging signals by an identifier forpaging signals and transmits them using the PMCH. A mobile terminalwhich needs to receive a paging signal, among mobile terminals beingserved by the MBMS dedicated cell, carries out blind detection by usingthe identifier for paging signals. As a result, there can be provided anadvantage of enabling such a mobile terminal to receive requiredinformation when the mobile terminal requires the information.Accordingly, there can be provided an advantage of reducing the powerconsumption of the mobile terminal. There can be provided a furtheradvantage of preventing a control delay time from occurring in themobile terminal. The identifier different for each information type canbe predetermined, or can be broadcast via broadcast information from aserving cell. As an alternative, the identifier different for eachinformation type can be broadcast from an MBMS dedicated cell.Furthermore, because each of the mobile terminals becomes able to carryout blind detection when the paging signal is multiplied by or added toa mobile-terminal-specific identifier, it becomes unnecessary to fix thephysical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, the mapping can becarried out with flexibility, and there is provided an advantage ofimproving the use efficiency of the physical resources.

Another example of the method of mapping paging signals onto thephysical area on the PMCH onto which the paging signals are to be mappedis shown in FIG. 34. In FIG. 34, the same reference numerals as those inFIG. 33 denote the same processes or like processes. Paging signals tomobile terminals n1, n2, and so on for each of which an incoming call isoccurring, among mobile terminals belonging to a paging group n, aremapped onto a physical area corresponding to this group n. Abase stationperforms CRC (Cyclic Redundancy Check) addition on the paging signaldestined for each of the mobile terminals (process 2), and carries out aprocess including encoding and rate matching (process 3). The result ofthese processes performed on the paging signal is multiplied by anidentification code (number) specific to the above-mentioned mobileterminal (process 7). This mobile-terminal-specific identification codeis a scrambling code having orthogonality which is established among theresults of the processes by the scrambling codes of mobile terminals.The base station carries out multiplexing of the results of theprocesses by the scrambling codes, the number of the multiplexed resultsof the processes by the scrambling codes being equal to the number ofmobile terminals for each of which an incoming call is occurring(process 8). The base station then performs a scrambling process usingan MBSFN-area-specific scrambling code, a modulation process, etc. onthe result of the multiplexing (process 5). The modulation process canbe specific to the MBSFN area. The result of carrying out theseprocesses is mapped onto the physical area corresponding to the paginggroup n (process 6). In this case, the base station sets “1” to thepaging signal presence or absence indicator (indicator 1) of the paginggroup n, and then maps it onto a physical area corresponding to thepaging group n of the paging signal presence or absence indicator. Thephysical area corresponding to the paging group n can be predetermined,or can be informed, as broadcast information, from either a unicast sideserving cell or an MBMS dedicated cell to the base station.

Each of the mobile terminals receives the paging signal presence orabsence indicator of the paging group to which the mobile terminalitself belongs, and, when the paging signal presence or absenceindicator has a value of “1”, receives the physical area for pagingsignal corresponding to this paging group. Each of the mobile terminalsreceives the physical area for paging signal, and carries outdemodulation and descrambling using the MBSFN-area-specific scramblingcode. Each of the mobile terminals carries out blind detection of thepaging signal destined for the mobile terminal itself by carrying out anoperation of calculating a correlation with the identification numberspecific to the mobile terminal itself. When the result of thecorrelation operation is larger than a certain threshold, each of themobile terminals determines that there is paging destined for the mobileterminal itself, and starts an operation of receiving a paging with thedecoded paging signal. In contrast, when the result of the correlationoperation is equal to or smaller than the certain threshold, each of themobile terminals determines that there is no paging destined for themobile terminal itself, and makes a transition to reception ofMBMS-related information or makes a transition to a DRX operation ifthere is no necessity to receive any MBMS-related information. To whichgroup each of the mobile terminals belongs can be determined by using apredetermined determining method, or can be informed, as broadcastinformation, from either a serving cell for unicast service or an MBMSdedicated cell to the mobile terminal itself via an upper layer. Insteadof the paging signals described in FIGS. 33 and 34, a transport channelonto which the paging signals are mapped can be provided. This methodcan also be applied to the subsequent embodiments. What is necessary isto use information on which the paging signals are carried, theinformation being paging-related information which each mobile terminalrequires when receiving a paging.

Some methods of mapping paging signals onto an area on the PMCH on whichthe paging signals are to be mapped are disposed, though the mapping canbe alternatively performed in such a way that the above-mentioned areaonto which the paging signals are to be mapped is an arbitrarypredetermined area, a localized area (a physical area continuous on thefrequency axis), or distributed areas (physical areas distributed on thefrequency axis).

In the above-mentioned example, the base station is configured in such away as to multiply the paging signal destined for each mobile terminalby a mobile-terminal-specific identification number or a scramblingcode. Because the base station is configured in this way, when theamount of information of the paging signal is the same at each of themobile terminals, it becomes able to equalize the sizes of the areas ofthe information element units to be allocated by making the processincluding encoding and rate matching be common among the mobileterminals. Therefore, because the sizes of the areas of the informationelement units on which each mobile terminal performs blind detection arelimited to a single one, the number of times that blind detection iscarried out can be reduced and the time required for blind detection canalso be shortened. Therefore, there is provided an advantage ofaccomplishing reduction in the circuit configuration of each mobileterminal, reduction in the power consumption of each mobile terminal,and reduction in the control delay of each mobile terminal.

By multiplying the paging signal destined for each of the mobileterminals by the mobile-terminal-specific identification number or thescrambling code, and then mapping it onto the area of the PMCH ontowhich the paging signal is mapped for each paging group, as mentionedabove, the necessity for each of the mobile terminals to receive all ofthe area for paging signals can be eliminated, and each of the mobileterminals has only to receive only a required area, i.e., a physicalarea corresponding to the group to which the mobile terminal itselfbelongs. Therefore, the length of time required for each of the mobileterminals to detect the paging signal destined therefor can beshortened. Furthermore, because each of the mobile terminals does nothave to receive the physical area corresponding to any other group towhich the mobile terminal itself does not belong, the power forreceiving of each of the mobile terminals can be reduced. In addition,by using the paging signal presence or absence indicator correspondingto each group, also when there are many mobile terminals, the pagingsignal presence or absence indicators can be provided with a smallamount of physical resources. Furthermore, each of the mobile terminalshas only to receive an area dedicated to paging signals as needed.Therefore, while the power for receiving of each of the mobile terminalscan be reduced, the control delay can also be reduced because each ofthe mobile terminals can make a transition to the next operationimmediately when it does not have to receive the paging signal. As aresult, because each of the mobile terminals becomes able to carry outblind detection (Blind Detection) of whether or not it is informationdestined for the mobile terminal itself by using the identification codespecific to the mobile terminal or the scrambling code, it becomesunnecessary to fix the physical area onto which the paging signaldestined for each of the mobile terminals is mapped in advance.Therefore, there is no necessity to provide a physical area used forpaging signals destined for all the mobile terminals, and a physicalarea which is large enough to map paging signals destined for a certainnumber of mobile terminals for each of which an incoming call ispredicted to actually occur has only to be provided. By using thismethod, it becomes able to use the limited amount of physical resourceseffectively. Furthermore, by using the above-mentioned method, themobile communication system can flexibly deal with even a case in whichthe number of mobile terminals for each of which an incoming call isoccurring becomes larger than a predicted number through scheduling in abase station. For example, the mobile communication system can transmita paging signal destined for a mobile terminal receiving anew incomingcall on the PMCH onto which the next MCCH is mapped.

In the above-mentioned example, the base station multiplies the pagingsignal destined for each mobile terminal by a mobile-terminal-specificidentification number. As an alternative, the base station can use amethod of multiplying a CRC, instead of the paging signal, by amobile-terminal-specific identification number. The method ofmultiplying a CRC by a mobile-terminal-specific identification number iseffective for a case in which the amount of information of the pagingsignal destined for each mobile terminal differs. By using the method ofcarrying paging signals on the PMCH which is disclosed above, the mobilecommunication system can transmit the paging signals destined for allmobile terminals each of which is receiving or trying to receive an MBMSservice from an MBMS dedicated cell to make it possible for each of theabove-mentioned mobile terminals to receive the paging signal from theMBMS dedicated cell.

Hereafter, the structure of a channel onto which paging signals in afrequency layer dedicated to MBMS transmission are mapped will beexplained with reference to an example shown in FIGS. 32(c) and 33. AnMCE, in step ST1779, carries out scheduling of the paging signaldestined for a mobile terminal in question. More specifically, the MCEdetermines to the how-manyth one of information elements mapped onto thephysical area allocated to the number of the paging group of the mobileterminal in question determined in step ST1778 an identifier of themobile terminal in question is allocated. By making the MCE carry outthis scheduling, an identifier of the mobile terminal in question istransmitted from the same physical resources of base stations includedin the MBSFN area. As a result, there can be provided an advantage ofenabling each mobile terminal to receive a paging signal benefiting froman SFN gain by receiving the PMCH which is transmitted via a multi-celltransmission scheme in the MBSFN area. The MCE, in step ST1780,transmits a paging request for the mobile terminal in question to thebase stations in the MBSFN area. The MCE transmits the paging requestfor the mobile terminal in question to the base stations included in theTA(MBMS). The MCE transmits the paging request for the mobile terminalin question to an MBMS dedicated cell included in the TA(MBMS). As anexample of parameters included in the paging request, an identifier(UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal, the result ofthe scheduling of the paging signal carried out in step ST1779(concretely, an SFN, an MBSFN subframe number, and an informationelement number), etc. can be considered. Each of the base stations inthe MBSFN area, in step ST1781, receives the paging request from theMCE.

Instead of disposing only an IF between MME and MCE between the MME 103and the MCE 801, as shown in FIG. 10, an MME-MBMS GW interface can alsobe disposed between the MME 103 and an MBMS GW 802 (in more detail, anMBMS CP 802-1). Furthermore, the processes of steps ST1776 to ST1780,which are carried out by the MCE, can be carried out by the MBMS GW onbehalf of the MCE. In this variant, the same advantages as thoseprovided by the present invention are provided.

Each of the base stations in the MBSFN area, in step ST1782, determinesthe paging group of the mobile terminal in question. As an example ofthe determining method, there is a method of determining the paginggroup of the mobile terminal in question by using the number K_(MBMS) ofpaging groups of the base station itself (the MBSFN area to which thebase stations belong), and the received paging request. When determiningthe paging group of the mobile terminal in question, each of the basestations uses the same computation expression as that used by the mobileterminal side (paging group=IMSI mod K_(MBMS)). When the MCE, in stepST1780, also informs the paging group of the mobile terminal inquestion, step ST1782 can be omitted. As a result, there can be providedan advantage of reducing the control load on each base station in theMBSFN area, and so on. In contrast, in accordance with the method of, instep ST1782, determining the paging group in each base station in theMBSFN area without informing the paging group of the mobile terminal inquestion in step ST1780, there can be provided an advantage of beingable to reduce the amount of information notified from the MCE to eachbase station in the MBSFN area, and making effective use of theresources. Each of the base stations in the MBSFN area, in step ST1783,transmits the PMCH on which the paging signal is mapped by using theidentifier of the mobile terminal in question received in step ST1781,the result of the scheduling of the paging signal, the paging group ofthe mobile terminal in question determined in step ST1782, etc. Morespecifically, each of the base stations maps the UE-ID of the mobileterminal in question onto a specified information element number of thecorresponding group of the paging-related PMCH, and sets an indicatorshowing the presence or absence of a paging-related change in thecorresponding group to “presence of change”. The previously-explainedmethods can be used as the mapping method of mapping the UE-ID to thepaging-related area in the PMCH at that time and a concrete mappingmethod of mapping the UE-ID to a physical channel, etc.

The mobile terminal, in step ST1784, receives a paging-related modifiedor unmodified indicator in the PMCH, the indicator corresponding to thepaging group determined in step ST1735 of the mobile terminal itself.The mobile terminal, in step ST1785, determines whether or not there isa change in the paging-related modified or unmodified indicator. Whenthere is no change in the paging-related modified or unmodifiedindicator, the mobile terminal makes a transition to step ST1788. Incontrast, when there is a change in the paging-related modified orunmodified indicator, the mobile terminal makes a transition to stepST1786. The mobile terminal then, in step ST1786, receives and decodesthe physical area onto which the paging-related information of thepaging group of the mobile terminal itself is mapped. At that time, themobile terminal carries out blind detection by carrying out an operationof calculating a correlation with the mobile-terminal-specificidentification code. The mobile terminal, in step ST1787, determineswhether it has detected the identifier of the mobile terminal itselfthrough the blind detection carried out in step ST1786. When the mobileterminal has not detected the identifier of the mobile terminal itself,the mobile terminal makes a transition to step ST1788. In contrast, whenthe mobile terminal has detected the identifier of the mobile terminalitself, the mobile terminal makes a transition to step ST1814. Theprocesses explained in above-mentioned steps ST1773 to ST1787 are anexample of the “discontinuous reception configuration at the time ofMBMS reception” described in Embodiment 1. As a result, there can bedisclosed a method of transmitting a paging signal to a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBMS transmission, and a mobile communication system which enables themethod to be implemented therein, which are a challenge of the presentinvention. Therefore, there is provided an advantage of enabling even amobile terminal currently receiving an MBMS service in a frequency layerdedicated to MBMS transmission to receive a paging signal.

Next, the “MTCH reception”, which is described in Embodiment 1 withreference to FIG. 17, will be explained more concretely with referenceto FIGS. 22 and 23. The mobile terminal, in step ST1788, determineswhether it is continuously receiving an MBMS service in the MBSFN areain question. When the mobile terminal is not continuously receiving anMBMS service in the MBSFN area, the mobile terminal makes a transitionto step ST1792. In contrast, when the mobile terminal is continuouslyreceiving an MBMS service in the MBSFN area, the mobile terminal makes atransition to step ST1789. The mobile terminal, in step ST1789, receivesan MBMS-related modified or unmodified indicator in the PMCH. The mobileterminal, in step ST1790, determines whether or not there is a change inthe MBMS-related modified or unmodified indicator. When there is nochange in the MBMS-related modified or unmodified indicator, the mobileterminal makes a transition to step ST1791. In contrast, when there is achange in the MBMS-related modified or unmodified indicator, the mobileterminal makes a transition to step ST1792. Because there is no changein the MCCH at the receiving time of receiving the MCCH, the mobileterminal, in step ST1791, does not carry out reception and/or decodingof the MBMS-related information in the MCCH. The mobile terminal carriesout reception and decoding of the MTCH without updating the controlinformation (MCCH). The mobile terminal, in step ST1792, carries outreception and decoding of the MBMS-related information in the MCCH toupdate the control information. The mobile terminal, in step ST1793,carries out reception and decoding of the MTCH according to the controlinformation received in step ST1792.

The mobile terminal, in step ST1794 of FIG. 23, measures the quality ofreception of the MBMS service which the mobile terminal is receiving.The mobile terminal receives a reference signal (RS) with the radioresources of the MBSFN area in question, and measures the received power(RSRP). The mobile terminal then determines whether or not the receivedpower is equal to or higher than a threshold determined statically orsemi-statically. The fact that the received power is equal to or higherthan the above-mentioned threshold shows that the mobile terminal hashigh sensitivity enough to receive the MBMS service, whereas the factthat the received power is lower than the threshold shows that themobile terminal does not have high sensitivity enough to receive theMBMS service. When the received power is equal to or higher than theabove-mentioned threshold, the mobile terminal makes a transition tostep ST1795, whereas when the received power is lower than theabove-mentioned threshold, the mobile terminal makes a transition tostep ST1796. Instead of receiving the reference signal and measuring thereceived power in step 1794, the mobile terminal can actually receiveand decode the MBMS service (an MTCH and/or an MCCH) of the MBSFN areain question. In this case, the user can determine whether the mobileterminal provides receive sensitivity which he or she can permit byhearing or viewing decoded data. When the mobile terminal providesreceive sensitivity which he or she can permit, the mobile terminalmakes a transition to step ST1795, whereas when the mobile terminal doesnot provide receive sensitivity which he or she can permit, the mobileterminal makes a transition to step ST1796. Because the permissiblereceive sensitivity has differences among individuals, there can beprovided an advantage of making mobile terminals be further suited forusers. The mobile terminal, in step ST1795, checks to see the user'sintention. When the user desires to succeedingly receive the MBMSservice which the mobile terminal is receiving, the mobile terminalmakes a transition to step ST1753. In contrast, when the user desires toend the reception of the MBMS service which the mobile terminal isreceiving, the mobile terminal makes a transition to step ST1798. Themobile terminal, in step ST1796, determines whether there exists anotherMBMS area in which the mobile terminal can receive the MBMS servicewithin the same frequency band (f(MBMS)). This step ST1796 is effectiveparticularly when an MBSFN area covering other MBSFN areas exists. Whenanother MBMS area receivable within the same frequency band exists, themobile terminal returns to step ST1730 and repeats the process. Incontrast, when any other MBMS area receivable within the same frequencyband does not exist, the mobile terminal makes a transition to stepST1797.

However, after that, unless any other receivable MBSFN area which theuser desires is found, the mobile terminal performs an “MBMS receptionend A” process in step ST1798 and subsequent steps. Accordingly, thenetwork side can know that the mobile terminal in question ends thereception of the MBMS service in the frequency layer dedicated to MBMStransmission. Therefore, the network side can discontinue theconfiguration of transmitting the paging signal to the mobile terminalin question in the frequency layer dedicated to MBMS transmission. As aresult, the mobile communication system becomes able to discontinue thetransmission of the paging signal to the mobile terminal in questionfrom the frequency layer dedicated to MBMS transmission which the mobileterminal in question does not receive. Therefore, there is provided anadvantage of making a effective use of the radio resources. The mobileterminal, in step 1797, determines whether or not there is anotherfrequency in the frequency list of the receivable MBSFN synchronizationarea received in step ST1708. When there is another frequency in thefrequency list, the mobile terminal returns to step ST1722, and switchesthe synthesizer to a new frequency (f2(MBMS)) and repeats the process.In contrast, when there is no other frequency in the frequency list, themobile terminal makes a transition to step ST1798.

Next, the “MBMS reception end A” process described in Embodiment 1 withreference to FIG. 23 will be explained more concretely. The mobileterminal, in step ST1798, moves to an MBMS/Unicast-mixed cell bychanging the frequency set to the frequency converting unit 1107 thereofto change the center frequency to f(unicast). Because the explanation ofsteps ST1799 to ST1803 is the same as that of steps ST1737 to ST1741,the explanation of steps ST1799 to ST1803 will be omitted. The mobileterminal, in step ST1804, transmits an “MBMS reception end” notificationto the serving cell according to UL (Uplink) allocation received in stepST1803. As an example of the parameters included in the “MBMS receptionend” notification, an identifier (UE-ID, IMSI, S-TMSI, or the like) ofthe mobile terminal, the frequency (f(MBMS)) at which the mobileterminal ends the reception of the MBMS service, and the MBSFN areanumber (ID) are included.

Furthermore, the “MBMS reception end” notification of step ST1804 can bemade like in the case of an “attach request” shown in ST1710, or as atype of “attach request”. As an alternative, the “MBMS reception end”notification can be made like in the case of “tracking area update(Tracking Area Update: TAU)”, or as a type of “tracking area update”.Parameters to be notified in this case includes an identifier (UE-ID,IMSI, S-TMSI, or the like) of the mobile terminal, the frequency(f(MBMS)) at which the mobile terminal ends the reception of the MBMSservice, and the MBSFN area number (ID), like in the above-mentionedcase. As a result, the network side is enabled to know that the mobileterminal has ended the reception of the MBMS in the MBMS dedicated cellwithout adding any new message. Therefore, there can be provided anadvantage of being able to avoid the complexity of the mobilecommunication system.

Information showing that the “tracking area update” includes the “MBMSreception end” notification can be included in the “tracking areaupdate”. As a concrete method, the “MBMS reception end” notification canbe added to the type (TYPE) information of TAU. The type information canbe expressed as a numerical value. A 1-bit indicator showing whether ornot to aim to make the “MBMS reception end” notification is formed onthe TAU request message. Information showing that the “attach request”message includes the “MBMS reception end” notification can be includedin the “attach request” message. As a concrete method, the “MBMSreception end” notification can be added to the type information of theattach request. The type information can be expressed as a numericalvalue. A 1-bit indicator showing whether or not to aim to make the “MBMSreception end” notification can be formed on the attach request message.As a result, in the former case, the conventional “tracking area update”can be distinguished from the “tracking area update” used in order toinform the “MBMS reception end”. Furthermore, in the latter case, theconventional “attach request” can be distinguished from the “attachrequest” used in order to inform the “MBMS reception end”. As a result,there can be provided an advantage of preventing a control delay timefrom occurring in the mobile communication system.

The serving cell, in step ST1805, receives the MBMS reception endnotification from the mobile terminal. The network side, in step ST1805,can know that the mobile terminal in question has ended the reception ofthe MBMS service in the frequency layer dedicated to MBMS transmissionwithout adding any uplink channel to the MBMS dedicated cell. As aresult, there is provided an advantage of enabling the generalconfiguration in which the network side informs paging signals to bechanged into the configuration of carrying out discontinuous receptionat the time of MBMS reception. The serving cell, in step ST1806,transmits the MBMS reception end notification to the MME. The MME, instep ST1807, receives the MBMS reception end notification from theserving cell.

The MME, in step ST1808, searches for the TA(MBMS) at which to end theMBMS reception of the mobile terminal in question. Because an example ofa relationship between parameters included in the MBMS reception endnotification and the TA(MBMS) is the same as that shown in step ST1747,the explanation of the example will be omitted. The MME, in step ST1809,deletes the TA(MBMS) which it has acquired, as the result of the searchof step ST1808, from the tracking area list of the mobile terminal inquestion. The MME, in step ST1810, transmits Ack which is a responsesignal to the serving cell when receiving a signal informing the MBMSreception end sent thereto via the serving cell. As an example ofparameters included in this response signal Ack, the tracking area listof the mobile terminals in question can be considered. The serving cell,in step ST1811, receives the response signal Ack transmitted from theMME. The serving cell, in step ST1812, transmits the received responsesignal Ack to the mobile terminal. The mobile terminal, in step ST1813,receives the response signal Ack sent thereto from the MME via theserving cell.

Next, “unicast side discontinuous reception” described in Embodiment 1will be explained more concretely with reference to FIG. 24. The MME inwhich paging has occurred, in step ST1814, checks to see the trackingarea list of the mobile terminals in question on the basis of anidentifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal inquestion for which the paging is destined. The MME then searches throughthe tracking area list of the mobile terminals in question for theTA(Unicast). As an example, the MME searches through the tracking arealist of the mobile terminal in question, such as the list shown in FIG.31(a), on the basis of the UE-ID of the mobile terminal. When the mobileterminal in question is the UE#1 of FIG. 31(a), TA(Unicast)s #1 and #2are included in the tracking area list. Next, the MME searches throughthe list as shown in FIG. 31(b) for the identifiers (cell IDs) of basestations included in the TA (Unicast). When the mobile terminal inquestion is the UE#1 of FIG. 31(a), the cell IDs included in thetracking area list of the mobile terminal in question are the ones of 1,2, 3, 4, 5, 23, 24, and 25. The MME transmits a paging request to thebase stations (including the serving cell) included in the tracking arealist of the mobile terminal in question. As an example of parametersincluded in the paging request, an identifier (UE-ID, IMSI, S-TMSI, orthe like) of the mobile terminal, etc. are included. Each of the basestations (including the serving cell) included in the tracking area list(TA(Unicast)) of the mobile terminal in question, in step ST1815,receives the paging request.

Hereafter, a challenge of the present invention will be explained. Alsofor a mobile terminal being in an idle state (Idle State) in anMBMS/Unicast-mixed cell, no details of any method of notifying a pagingmessage are established. Nonpatent reference 1 discloses that a PCH ismapped onto a PDSCH or a PDCCH. Nonpatent reference 1 also disclosesthat a paging group uses an L1/L2 signaling channel (PDCCH) and that aprecise identifier (UE-ID) of a mobile terminal can be found on a PCH.In contrast, nonpatent reference 1 does not disclose how mobileterminals are divided into paging groups and how a PCH is transmitted toeach of the paging groups. Furthermore, nonpatent reference 1 does notdisclose how a mobile terminal carries out discontinuous reception in anidle state. It is an object of the present invention to disclose thedetails of a sending method of sending a paging signal to a mobileterminal in an idle state in a unicast and/or mixed frequency layer, anda mobile communication system which enables the method to be implementedtherein.

Therefore, an example of the sending method of sending a paging signalwill be disclosed hereafter. Mobile terminals are divided into paginggroups. In accordance with a conventional technology (W-CDMA system),the number of S-CCPCHs (Secondary Common Control CHannels) (the numberof channelization codes) onto which a PCH is mapped is defined as thenumber of the groups. However, because an LTE system is not based on acode division multiplexing (CDM) method, an idea of using the number ofchannelization codes cannot be applied to the present invention.Nonpatent reference 1 provided by the current 3GPP discloses that apaging group uses an L1/L2 signaling channel (PDCCH) and that a preciseidentifier (UE-ID) of a mobile terminal can be found on a PCH. However,no concrete example is disclosed. K_(Unicast) in a computationexpression for determining a paging group (IMSI mod K_(Unicast)) is thenumber of paging groups in an MBMS/Unicast-mixed cell. In an example ofthe value of K, the L1/L2 signaling channel (PDCCH) is mapped for eachsubframe. Ten subframes exist in one radio frame. Therefore, the numberof paging groups is set to ten. More specifically, each mobile terminalcan know onto which subframe in one radio frame the paging informationabout the paging group to which the mobile terminal itself belongs ismapped from the paging group. As to onto which radio frame the paginginformation about the group to which each mobile terminal belongs ismapped, a conventional technology (W-CDMA) can be followed. A concretecomputation expression is given by “Paging Occasion=(IMSI div K) mod(the discontinuous reception cycle length in a unicast/mixed frequencylayer)+n×(the discontinuous reception cycle length in a unicast/mixedfrequency layer), where n: 0, 1, 2, . . . , and a maximum of SFN”. Aconcrete computation expression is alternatively given by “PagingOccasion=(IMSI div K_(Unicast)) mod (the discontinuous reception cyclelength in a unicast/mixed frequency layer)+n×(the discontinuousreception cycle length in a unicast/mixed frequency layer), where n: 0,1, 2, . . . , and where Paging Occasion a maximum of SFN”. SFN is aninteger ranging from 0 to the maximum of SFN.

Next, it is disclosed in nonpatent reference 1 provided by the current3GPP that a precise identifier (UE-ID) of a mobile terminal can be foundon a PCH. However, no concrete example is disclosed. In a concreteexample of a mapping method of mapping paging information to a PCH, thePCH consists of identification information about a mobile terminal, oris configured in such a way to show a correlation when multiplied byidentification information about a mobile terminal. The PCH is mappedonto CCEs on the L1/L2 signaling channel. Furthermore, it is assumedthat allocation of downlink radio resources of a control channel whichthe mobile terminal should receive the next time is included in the PCH.As a result, there can be provided an advantage of eliminating thenecessity to carry out downlink allocation for the second time, andbeing able to reduce the control delay. As an alternative, a method ofnot sending allocation of downlink radio resources of a control channelwhich the mobile terminal should receive the next time using the PCH canbe used. As this method, there can be considered a method oftransmitting a paging indicator on an L1/L2 signaling channel, andmaking a mobile terminal which carries out blind detection of the pagingindicator destined for itself to receive the paging indicator transmitan uplink RACH in order to make a request of a base station for resourceallocation. The PCH in which the precise identifier (UE-ID) of a mobileterminal is included can be transmitted on a PDSCH. In this case,information about allocation of radio resources of the PDSCH onto whichthis PCH which the mobile terminal should receive is mapped is mapped,as a paging indicator, onto the L1/L2 signaling channel. In a case inwhich the paging indicator is configured in such a way to show acorrelation when multiplied by the identification information about themobile terminal, the mobile terminal becomes able to determine whetheror not the paging indicator is destined for itself. The mobile terminalwhich has received the paging indicator destined for itself receives theidentification information included in the PCH on the PDSCH on the basisof the allocation information to check to see whether it shows themobile terminal itself. In the case in which the method is configured inthis way, the mobile terminal becomes able to certainly detect whetheror not the paging signal is destined for the mobile terminal itself, andcan prevent itself from performing an erroneous reception operation.

Each of the base stations (including the serving cell) included in thetracking area list (TA(Unicast)) of the mobile terminal in question, instep ST1816, makes preparations for unicast side discontinuousreception. Concretely, each of the base stations determines a paginggroup and a paging occasion from the identifier of the mobile terminalin question which each of the base stations receives in step ST1815. Anexample of a computation expression for determining them is as mentionedabove. Each of the base stations (including the serving cell) includedin the tracking area list (TA (Unicast)) of the mobile terminal inquestion, in step ST1817, maps the paging information about the mobileterminal in question onto the PCH according to the paging group and thepaging occasion which each of the base stations determines in stepST1816. At this time, each of the base stations can map the paginginformation to any CCEs as long as these CCEs are included in the L1/L2signaling channel in the subframe shown by the above-mentioned paginggroup in the radio frame shown by the above-mentioned paging occasion.As an alternative, each of the base stations can map the paginginformation onto CCEs which are predetermined to be allocated to thePCH. In a case in which CCEs are predetermined to be allocated to thePCH, because the number of times that the mobile terminal in questioncarries out blind detection is reduced, there can be provided anadvantage of reducing the control delay. Each of the base stations(including the serving cell) included in the tracking area list (TA(Unicast)) of the mobile terminal in question, in step ST1818, transmitsthe PCH.

The mobile terminal, in step ST1819, moves to the unicast/mixedfrequency layer by changing the frequency set to the frequencyconverting unit 1107 thereof to change the center frequency to f(unicast). The mobile terminal, in step ST1820, makes preparations forunicast side discontinuous reception. Concretely, the mobile terminaldetermines the paging group and the paging occasion from the identifierof the mobile terminal itself. A computation expression for determiningthem is the same as that for use in the network side as mentioned above.The mobile terminal, in step ST1821, carries out blind detection of thePCH on the L1/L2 signaling channel according to the paging group and thepaging occasion which the mobile terminal determines in step ST1820. Themobile terminal uses the identifier of the mobile terminal itself forthe blind detection. The mobile terminal multiplies each of the CCEs ofthe PCH by the identifier of the mobile terminal itself to acquire acorrelation value. When the correlation value is equal to or larger thana threshold, the mobile terminal determines that there is a pagingdestined for the mobile terminal itself. The mobile terminal, in stepST1822, decodes the PCH to acquire the downlink allocation of the nextcontrol channel. According to the allocation, the mobile terminalreceives the control information.

In the current 3GPP, it is determined that in a mixed cell, anythingother than one or two leading OFDM symbols in each subframe must not beused for unicast transmission in an MBSFN frame (subframe). In otherwords, anything other than one or two leading OFDM symbols is a resourcededicated to MBMS transmission. An MBSFN frame is a subframe which isnot allocated to any of subframes #0 and #5 because an SCH is mappedonto them. In this case, the following problems occur. If theabove-mentioned computation expression for determining a paging groupand a paging occasion is used, there is a possibility that a pagingsignal occurs for each radio frame and for each subframe. Because thePCH uses the L1/L2 signaling channel, the PCH can be mapped even onto anMBSFN frame. On the other hand, in a case in which allocation of adownlink radio resource to the next control information using the PCH iscarried out in an MBSFN frame, because the downlink radio resource inthe same subframe is used exclusively for MBMS transmission, therearises a problem that the control information cannot be allocated to thesame subframe. As a solution of the problem, allocation of a downlinkradio resource to the next control information using the PCH is aimed ata radio frame other than the subsequent MBSFN frames. As anothersolution of the problem, a method of allocating the paging signal to oneor more subframes excluding subframes which can be MBSFN subframes isused. For example, the number of paging groups is set to be equal to orsmaller than the number of subframes excluding subframes which can beMBSFN subframes in one radio frame. As a result, the paging signal doesnot have to be allocated to an MBSFN subframe. As a concrete example,the number of paging groups is set to 2, and a computation expressionfor determining the paging group is given by “IMSI mod 2”, as will bementioned below. In a concrete example of group allocation, when thepaging group=0, a subframe #0 is allocated. Furthermore, when the paginggroup=1, a subframe #5 is allocated. As a result, because it becomesable to inform paging information by using only the subframe (#0 or #5)to which no MBSFN subframe is allocated, the above-mentioned problemthat allocation of the next control information to a subframe which isthe same as that to which the paging signal is allocated cannot becarried out can be solved.

Furthermore, as another solution of the problem, there is a method ofnot sending allocation of a downlink radio resource to the controlchannel, which the mobile terminal should receive the next time, byusing the PCH. In this method, a paging indicator is transmitted on theL1/L2 signaling channel, and the mobile terminal which has carried outblind detection of the paging indicator destined for itself to receivethe paging indicator transmits an uplink RACH to a base station in orderto make a request of the base station for resource allocation. Becausethe method is configured in this way, it is not necessary to carryresource allocation information on the PDSCH for communications afterthe paging, and therefore it becomes able to transmit and receive thepaging signal without any problems even if an MBSFN subframe exists. Inthis case, the paging indicator is configured in such a way to show acorrelation when multiplied by the identification information about themobile terminal so that the mobile terminal can be identified by usingonly the paging indicator. In an MBSFN subframe, what is necessary isjust to carry the paging indicator on an area which is allocated forunicast, i.e., one or two leading OFDM symbol areas. Also in this case,the paging indicator is similarly configured in such a way to show acorrelation when multiplied by the identification information about themobile terminal so that the mobile terminal can be identified by usingonly the paging indicator. The mobile terminal side can receive a radioframe or a subframe onto which the paging indicator of the group towhich the mobile terminal belongs is mapped, the group being determinedfrom the identification number specific to this mobile terminal, and tocarry out blind detection by using the identification number specific tothe mobile terminal itself.

As a concrete computation expression for determining a paging group anda paging occasion, the following equation can be used as mentionedabove.

IMSI mod K, where K is the number of paging groups in theMBMS/Unicast-mixed cell.

Paging Occasion=(IMSI div K) mod (the discontinuous reception cyclelength in a unicast/mixed frequency layer)+n×(the discontinuousreception cycle length in a unicast/mixed frequency layer), where n: 0,1, 2, . . . , and where Paging Occasion≦a maximum of SFN. SFN is aninteger ranging from 0 to the maximum of SFN.

Because the method is configured in this way, also in the case of theMBMS/Unicast-mixed cell, the paging signal (the paging indicator) can betransmitted with an arbitrary radio frame or subframe regardless ofwhether or not there exists an MBSFN subframe.

The details of an MBMS reception end B process are shown in FIG. 24. InFIG. 24, because an explanation of steps ST1823 to ST1837 is the same asthat of steps ST1799 to ST1813, the explanation of steps ST1823 toST1837 will be omitted. The difference is that a “response to paging” isincluded in step ST1828. Through this MBMS reception end B process, thenetwork side can know that the mobile terminal in question has ended thereception of the MBMS service in the frequency layer dedicated to MBMStransmission without adding any uplink channel to the MBMS dedicatedcell. As a result, there is provided an advantage of enabling thediscontinuous reception configuration at the time of MBMS reception tobe changed to the general configuration of transmitting paging signals.

Furthermore, the “MBMS reception end” notification of step ST1828 can bemade like in the case of an “attach request” shown in ST1710, or as atype of “attach request”. As an alternative, the “MBMS reception end”notification can be made like in the case of “tracking area update(Tracking Area Update: TAU)”, or as a type of “tracking area update”.Parameters to be notified in this case includes an identifier (UE-ID,IMSI, S-TMSI, or the like) of the mobile terminal, the frequency(f(MBMS)) at which the mobile terminal ends the reception of the MBMSservice, the MBSFN area number (ID), and a response to the paging, likein the above-mentioned case. As a result, the network side is enabled toknow that the mobile terminal has ended the reception of the MBMS in theMBMS dedicated cell without adding any new message. Therefore, there canbe provided an advantage of being able to avoid the complexity of themobile communication system. Information showing that the “tracking areaupdate” includes the “MBMS reception end” notification can be includedin the “tracking area update”. As a concrete method, the “MBMS receptionend” notification can be added to the type (TYPE) information of TAU.The type information can be expressed as a numerical value. A 1-bitindicator showing whether or not to aim to make the “MBMS reception end”notification is formed on the TAU request message. Information showingthat the “attach request” message includes the “MBMS reception end”notification can be included in the “attach request” message. As aconcrete method, the “MBMS reception end” notification can be added tothe type information of the attach request. The type information can beexpressed as a numerical value. A 1-bit indicator showing whether or notto aim to make the “MBMS reception end” notification is formed on theattach request message.

As a result, in the former case, the conventional “tracking area update”can be distinguished from the “tracking area update” used in order toinform the “MBMS reception end”. Furthermore, in the latter case, theconventional “attach request” can be distinguished from the “attachrequest” used in order to inform the “MBMS reception end”. As a result,there can be provided an advantage of preventing a control delay timefrom occurring in the mobile communication system. Furthermore, the“MBMS reception end notification+response to paging” of step ST1828 canbe made like in the case of an “attach request” shown in ST1710, or as atype of “attach request”. As an alternative, the “MBMS reception endnotification+response to paging” can be made like in the case of“tracking area update (Tracking Area Update: TAU)”, or as a type of“tracking area update”. Parameters to be notified in this case includesan identifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal,the frequency (f(MBMS)) at which the mobile terminal ends the receptionof the MBMS service, and the MBSFN area number (ID), like in theabove-mentioned case. As a result, the network side is enabled to knowthat the mobile terminal has ended the reception of the MBMS in the MBMSdedicated cell without adding any new message. Therefore, there can beprovided an advantage of being able to avoid the complexity of themobile communication system.

Information showing that the “tracking area update” includes the “MBMSreception end notification+response to paging” can be included in the“tracking area update”. As a concrete method, the “MBMS reception endnotification+response to paging” can be added to the type (TYPE)information of TAU. The type information can be expressed as a numericalvalue. A 1-bit indicator showing whether or not to aim to make the “MBMSreception end notification+response to paging” is formed on the TAUrequest message. Information showing that the “attach request” messageincludes the “MBMS reception end notification+response to paging” can beincluded in the “attach request” message. As a concrete method, the“MBMS reception end notification+response to paging” can be added to thetype information of the attach request. The type information can beexpressed as a numerical value. A 1-bit indicator showing whether or notto aim to make the “MBMS reception end notification+response to paging”is formed on the attach request message. As a result, in the formercase, the conventional “tracking area update” can be distinguished fromthe “tracking area update” used in order to inform the “MBMS receptionend+response to paging”. Furthermore, in the latter case, theconventional “attach request” can be distinguished from the “attachrequest” used in order to inform the “MBMS reception end+response topaging”. As a result, there can be provided an advantage of preventing acontrol delay time from occurring in the mobile communication system.

In the above-mentioned example, the identifiers of the mobile terminalcan include the following ones. In the mobile communication system, themobile terminal identifiers can include a mobile terminal identifierwhich is used in the unicast/mixed frequency layer, and a mobileterminal identifier which is used in the frequency layer dedicated toMBSFN transmission. As examples of the mobile terminal identifier whichis used in the unicast/mixed frequency layer, there can be consideredUE-ID, IMSI, and S-TMSI which are conventionally used, and a mobileterminal identifier allocated for each cell. As an example of the mobileterminal identifier which is used in the frequency layer dedicated toMBSFN transmission, there can be considered an identifier which isallocated in common to a mobile terminal by base stations which carryout multi-cell transmission. As further examples, there can beconsidered a mobile terminal identifier which is newly disclosed in thepresent invention, and which is used (or allocated in common) within theTA(MBMS), the mobile terminal identifier being used for the mobileterminal in question, an identifier which is used (or allocated incommon) in an MBSFN area in which the mobile terminal in questionreceives an MBMS service, the identifier being used for the mobileterminal in question, and the mobile terminal identifier which is used(or allocated in common) in an MBSFN synchronization area.

By newly disposing the mobile terminal identifier as mentioned abovewhich is used in the frequency layer dedicated to MBSFN transmission,there can be provided the following advantages. In a case in which aconventional mobile terminal identifier allocated for each cell is used,because there is a possibility that an identifier allocated to a mobileterminal in question differs for each cell, it is impossible to carryout multi-cell transmission of information using the identifier.Therefore, it is impossible to perform SFN combining of informationusing a mobile terminal identifier allocated for each cell. Furthermore,in a case in which a conventional identifier IMSI or UE-ID is used, itis possible to carry out multi-cell transmission, but there is a problemin the effective use of the radio resources because the amount ofinformation of the identifier IMSI or UE-ID increases. Furthermore, theidentifiers IMSI and UE-ID have values statically determined for eachmobile terminal, and there is no opportunity to change any of them.Therefore, heavy use of the identifier IMSI or UE-ID in a wirelesssection increases the opportunity of tapping, etc., and causes a problemwith security.

Because an identifier as mentioned above in accordance with the presentinvention is used in either a TA(MBMS) or an MBSFN area, it is not theone, like an identifier IMSI, statically provided for each mobileterminal, but it has a value which is changed when, for example, theTA(MBMS) is changed. Therefore, even if the identifier encounterstapping, there is an opportunity to change the identifier and strongsecurity is therefore provided. As a result, by using a mobile terminalidentifier which is used in the frequency layer dedicated to MBSFNtransmission, while the problem with security and the problem with radioresources are solved, it becomes able to carry out multi-celltransmission of information using an identifier as mentioned above inaccordance with the present invention (the information can be multipliedby the identifier). Accordingly, there can be provided an advantage ofenabling SFN combining of information using the identifier of the mobileterminal which is used in the frequency layer dedicated to MBSFNtransmission to be carried out, and reducing receive errors detected inthe information received by the mobile terminal. This results inadvantages, such as prevention of a control delay time in the wholemobile communication system, and effective use of the radio resources.

An example of the operation will be shown hereafter. The mobileterminal, in step ST1742, transmits a “notification of the MBMS sidereceiving state” to the serving cell. As an example of parametersincluded in the “notification of the MBMS side receiving state”, anidentifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal,the frequency (f(MBMS)) at which the mobile terminal receives the MBMSservice, and the MBSFN area number (ID) are included. The MME, in stepST1746, determines a tracking area (referred to as a TA(MBMS) from hereon) in which the mobile terminal in question is receiving the MBMSservice at the frequency dedicated to MBMS transmission. At that time,the MME derives the identifier of the mobile terminal used in the MBSFNarea (can alternatively derive an identification code) by using themobile-terminal-specific identifier of the mobile terminal, the MBSFNarea ID, etc. which are acquired through the “notification of the MBMSside receiving state”. As an alternative, the MME can derive theidentifier of the mobile terminal used in the TA(MBMS) (canalternatively derive an identification code) by using themobile-terminal-specific identifier of the mobile terminal, the MBSFNarea ID, etc. The derived identifier of the mobile terminal can beallocated to a plurality of mobile terminals (i.e., the identifier isallocated to the group to which the mobile terminal belongs), or can bethe one specific to the mobile terminal. On behalf of the MME, an MCE oran MBMS GW can derive the identifier of the mobile terminal.

The derived identifier is transmitted from the MME to the mobileterminal via the serving cell, and is further transmitted from the MMEto an MCE. For example, the transmission of the derived identifier fromthe MME to the mobile terminal via the serving cell can be carried outin steps ST1748 to ST1750. The derived identifier does not necessarilyhave to be transmitted in these steps, and can be alternativelytransmitted via an dedicated signal (a DCCH, a DTCH or the like). TheMME, when transmitting a paging request to the MCE, e.g., in ST1776, caninform either the identifier of the mobile terminal used in the TA(MBMS)or the identifier of the mobile terminal used in the MBSFN area. In thetransmission from the MCE to the MBMS dedicated cell, the derivedidentifier can be transmitted together with the paging request ofST1780. Each base station in the MBSFN area, in step ST1783, maps eitherthe identifier of the mobile terminal used in the MBSFN area of themobile terminal in question, or the identifier of the mobile terminalused in the TA(MBMS) onto a PMCH. The mobile terminal, in step ST1787,determines whether the identifier of the mobile terminal itself isincluded in the result of receiving and decoding (whether it hasdetected the identifier). Similarly, insteps ST1710 to ST1719, stepsST1761 to ST1770, steps ST1804 to ST1813, steps ST1814 to ST1815, andsteps ST1828 to ST1837, the identifier of the mobile terminal which isused in the frequency layer dedicated to MBSFN transmission can be used.

Furthermore, not only in the case of this Embodiment but in a case inwhich multi-cell (MC) transmission is carried out for each MBSFN area,in the above-mentioned mobile communication system, the method ofincluding, as identifiers of each mobile terminal, a mobile terminalidentifier used in a unicast/mixed frequency layer and a mobile terminalidentifier used in a frequency layer dedicated to MBSFN transmission canbe used. More specifically, not only in the case of this Embodiment butin a case in which multi-cell (MC) transmission is carried out for eachMBSFN area, a mobile terminal identifier used for a mobile terminal inquestion which is used (or allocated in common) in a TA(MBMS), anidentifier used for the mobile terminal in question which is used (orallocated in common) in an MBSFN area where the mobile terminal inquestion is receiving an MBMS service, or the like can be used forinformation (the information can be multiplied by each of theidentifiers). As a result, there can be provided an advantage ofenabling the mobile terminal to carry out SFN combining of theinformation, and reducing receive errors detected in the informationreceived by the mobile terminal. This results in advantages, such asprevention of a control delay time in the whole mobile communicationsystem, and effective use of the radio resources. Introduction ofmulti-cell transmission even in a unicast/mixed frequency layer has beenalso studied. In this case, an identifier used for the mobile terminalin question which is used (or allocated in common) in an MBSFN areawhere the mobile terminal in question is receiving an MBMS service, orthe like can be used, as the identifier of the mobile terminal, forinformation (the information can be multiplied by each of theidentifiers). As a result, there can be provided an advantage ofenabling the mobile terminal to carry out SFN combining of theinformation, and reducing receive errors detected in the informationreceived by the mobile terminal. This results in advantages, such asprevention of a control delay time in the whole mobile communicationsystem, and effective use of the radio resources.

In this Embodiment 2, the case in which a frequency layer dedicated toMBMS transmission consists of an MBMS dedicated cell is described. ThisEmbodiment 2 can be applied to even a case in which a frequency layerdedicated to MBMS transmission consists of an MBMS/Unicast-mixed cell.Embodiments 3, 4, 5 and 6, as well as Embodiment 1, can also besimilarly applied to even a case in which a frequency layer dedicated toMBMS transmission consists of an MBMS/Unicast-mixed cell.

Embodiment 3

In the current 3GPP, existence of an MBSFN (Multimedia Broadcastmulticast service Single Frequency Network) area covering a plurality ofMBSFN areas has been debated. A conceptual diagram of the geographicallocations of base stations in a case in which an MBSFN area covering aplurality of MBSFN areas exists is shown in FIG. 28. Four MBSFN areas 1to 4 exist in a single MBSFN synchronization area (MBSFN SynchronizationArea). The MBSFN area 4 covers the other MBSFN areas 1 to 3. As thecontents of the debate about the MBSFN area 4 in the current 3GPP, it isonly that access to the MBSFN area (i.e., the MBSFN area 4) covering theother MBSFN areas is carried out via a covered MBSFN area (one of theMBSFN areas 1 to 3). It has not been determined whether to dispose anMCCH (multicast control channel) in the MBSFN area 4 covering the otherMBSFN areas 1 to 3. A detailed concrete operation in the case in whichan MCCH exists in the MBSFN area 4 is explained in Embodiment 2. In thisEmbodiment, a case in which no MCCH exists in the MBSFN area coveringthe other MBSFN areas will be explained. A conceptual diagram is shownin FIG. 35. An explanation will be made focusing on a portion differentfrom FIG. 29 which is referred to in the explanation of Embodiment 2.Portions which will not be explained particularly are the same as thoseexplained in Embodiment 2.

First, as a first difference between FIG. 35 and FIG. 29, there is adifference between a method of transmitting control information (anMCCH) in accordance with this Embodiment and that in accordance withEmbodiment 2 because no MCCH exists in the MBSFN area 4 shown in FIG.28. First, as a method of mapping an MCCH for the MBSFN area 4, therecan be considered a method of ensuring areas for the MBSFN areas 1 and 4in a PMCH (PMCH1) of an MBSFN area covered (the MBSFN area 1).

A conceptual diagram is shown in FIG. 36. FIG. 36 is an explanatorydrawing showing a method of mapping a paging-related signal into a PMCH(PMCH1) onto which a multicast control channel (MCCH1) is mapped inorder to send control information to the MBSFN area including theplurality of MBSFN areas. The configuration of the physical MCH (PMCH)in which areas for paging of the MBSFN areas 1 and 4 is disposed isshown in FIG. 36(a). The physical MCH is configured in such a way thatMBMS-related information about the MBSFN areas 1 and 4, andpaging-related information about the MBSFN areas 1 and 4 are included onthe PMCH (PMCH1). The MBMS-related information and the paging signal ofeach of the MBSFN areas can exist as information elements in an MTCH andan MCCH respectively, or time-division multiplexing of physical areas(resources) onto which the MBMS-related information and the pagingsignal are mapped respectively can be carried out. A configuration ofdisposing an indicator indicating whether or not the contents of theMCCH have been changed independently for each of the MBSFN areas 1 and 4in the physical MCH (PMCH) in which paging-related area of the MBSFNareas 1 and 4 is disposed is shown in FIG. 36(b). In FIG. 36(b), a casein which paging signal presence or absence indicators (indicators 1)each showing presence or absence of paging in a corresponding one of theMBSFN areas 1 and 4, and MBMS-related modified or unmodified indicators(indicators 2) each showing modification or unmodification inMBMS-related information in a corresponding one of the MBSFN areas 1 and4 are provided as the indicators is shown. A configuration in a case inwhich the paging-related modified or unmodified indicators(indicators 1) are divided into K groups is shown in FIG. 36(c). Whenthe method of ensuring, in the PMCH (PMCH1) of one covered MBSFN area(the MBSFN area 1), the areas for the MBSFN areas 1 and 4 is used inthis way, there can be provided an advantage of carrying out thescheduling of the MCCH1 to be informed via the BCCH1 (broadcast controlchannel) only for the MBSFN area 1. Because the details of thescheduling method of scheduling the MCCH are the same as those shown inEmbodiment 2, the details of the scheduling method will be omittedhereafter.

The scheduling method of scheduling the MCCH will be explained. Inaddition to the scheduling of the MCCH1 to be informed via the BCCH1,the starting point of a physical area onto which the MCCH4 is mapped hasonly to be informed. As an alternative, the scheduling to be informedvia the BCCH1 can be the one of the PMCH1.

As a second difference between the figures, there is a differencebetween a method of transmitting a paging signal destined for a mobileterminal currently receiving an MBMS service in the MBSFN area 4 andthat used in Embodiment 2 because no MCCH does not exist in the MBSFNarea (i.e., the MBSFN area 4) covering the other MBSFN areas. Thisdifference in the method of transmitting a paging signal will beexplained. First, there can be considered a method of enabling thenetwork side to inform a paging signal destined for a mobile terminal inquestion to all of the MBSFN areas 1 to 3 covered by the MBSFN area 4.This method can be implemented also in the case in which no MCCH existsin the MBSFN area 4 without adding any additional control to theconcrete method explained in Embodiment 2. This method is effective fromthe viewpoint of avoiding the complexity of the mobile communicationsystem.

Next, there can be considered a method of enabling the network side toinform a paging signal destined for a mobile terminal in question to anMBSFN area covered by the MBSFN area 4 (either of the MBSFN areas 1 to3), in which the mobile terminal is being located. A concrete operationwill be explained focusing on a point different from that shown inEmbodiment 2. A “notification of the MBMS side receiving state” will beexplained. The mobile terminal, in step ST1742 of FIG. 20, transmits a“notification of the MBMS side receiving state” to the serving cellaccording to UL (Uplink) allocation received in step ST1741. As anexample of parameters included in the “notification of the MBMS sidereceiving state”, an identifier (UE-ID, IMSI, S-TMSI, or the like) ofthe mobile terminal, the frequency (f(MBMS)) at which the mobileterminal receives the MBMS service, and the MBSFN area number (ID) areincluded. In this case, the MBSFN area ID informed to the serving cellis not the MBSFN area ID (MBSFN area 4) of the MBSFN area from which themobile terminal is actually receiving the MBMS service (MTCH), but isthe MBSFN area ID of the MBSFN area in which the mobile terminal isbeing located, this MBSFN area being covered by the MBSFN area 4. Inother words, the mobile terminal informs the MBSFN area ID mapped ontothe S-SCH (secondary synchronization channel) which it has received whenmaking an MBSFN search. As a result, the network side can know thecovered MBSFN area in which the mobile terminal is being actuallylocated. The mobile terminal further carries out a process of stepST3101 of FIG. 37 before carrying out a process of step ST1794 of FIG.23.

The mobile terminal, in step ST3101 of FIG. 37, measures the quality ofreception of the MCCH which the mobile terminal is receiving. The mobileterminal receives a reference signal (RS) with the radio resources ofthe MBSFN area in question, and measures the received power (RSRP). Themobile terminal then determines whether or not the received power isequal to or higher than a threshold determined statically orsemi-statically. The fact that the received power is equal to or higherthan the above-mentioned threshold shows that the mobile terminal hashigh sensitivity enough to receive the MCCH, whereas the fact that thereceived power is lower than the threshold shows that the mobileterminal does not have high sensitivity enough to receive the MCCH. Whenthe received power is equal to or higher than the above-mentionedthreshold, the mobile terminal makes a transition to step ST1794,whereas when the received power is lower than the above-mentionedthreshold, the mobile terminal makes a transition to step ST1724. As aresult, the mobile terminal recognizes the mobility between coveredMBSFN areas onto which the MCCH is mapped. This method provides moreeffective features as will be shown below as compared with the method ofenabling the network side to inform a paging signal destined for amobile terminal in question from all of the MBSFN areas 1 to 3 coveredby the MBSFN area 4. Because the mobile communication system becomesunnecessary to make any base station other than a base station fromwhich the mobile terminal in question can receive a paging signalgeographically (e.g., a base station in the MBSFN area 2 or 3 when themobile terminal in question is being located in the MBSFN area 1)transmit the paging signal, there is provided an advantage of makingeffective use of the radio resources. Also in this Embodiment, like inthe case of Embodiment 2, the method of including, as identifiers ofeach mobile terminal, a mobile terminal identifier used in aunicast/mixed frequency layer and a mobile terminal identifier used in afrequency layer dedicated to MBSFN transmission can be used.

In accordance with Embodiment 3, also in a case in which no MCCH existsin an MBSFN area covering a plurality of MBSFN areas, there is providedan advantage of being able to inform a paging signal to a mobileterminal currently receiving an MBMS service in an MBMS transmissiondedicated cell, which is a challenge of the present invention.Furthermore, the method of selecting a desired service in an MBMStransmission dedicated cell, which is a challenge of the presentinvention, can be disclosed. As a result, there is provided an advantageof enabling a mobile terminal to receive a desired service in an MBMStransmission dedicated cell in which no uplink channel exists.

Embodiment 4

The sending method of sending a paging signal when a mobile terminalcurrently receiving an MBMS service in an MBMS transmission dedicatedcell has a low paging reception capability (Capability) is described inEmbodiments 1 to 3. Next, a paging signal sending method in a case inwhich a mobile terminal having a high paging reception capability (ahigh-capability terminal) and a mobile terminal having a low pagingreception capability (a low-capability terminal) coexist will beexplained. As an example of a “low-capability terminal” which will bedescribed hereafter, there is a mobile terminal having a singlereceiver. Another example is a mobile terminal that can only determine asingle center frequency by changing the frequency set to the frequencyconverting unit 1107 thereof. Another example is a mobile terminal thatcannot carry out discontinuous reception of an MBMS/Unicast-mixed cellwhile receiving an MBMS service in an MBMS transmission dedicated cell.

As an example of a “high-capability terminal”, there is a mobileterminal having a plurality of receivers (e.g., two receivers). Anotherexample is a mobile terminal that can determine a plurality of centerfrequencies by changing the frequency set to the frequency convertingunit 1107 thereof. Another example is a mobile terminal that can carryout discontinuous reception in an MBMS/Unicast-mixed cell even whilereceiving an MBMS service in an MBMS transmission dedicated cell. FIG.38 is a table showing a concept of the capability of a mobile terminal.This capability (Capability) of a mobile terminal is informed, in stepST1710, from the mobile terminal to a serving base station, and isfurther informed, in step ST1712, from the serving base station to anMME. As a result, the network side can recognize the paging receptioncapability of the mobile terminal in question. Therefore, it becomesable to change the paging method of transmitting paging to a mobileterminal currently receiving an MBMS service in a frequency layerdedicated to MBMS transmission according to the paging receptioncapability of the mobile terminal.

A concrete example of operation will be explained with reference toFIGS. 16 and 17. A high-capability terminal carries out a receivingoperation of receiving a signal from an MBMS/Unicast-mixed cell, and areceiving operation of receiving a signal from an MBMS transmissiondedicated cell in parallel. As an example of the receiving operation ofreceiving a signal from an MBMS transmission dedicated cell, there aresteps ST1601-1, ST1602, ST1603, ST1604, and ST1609. Because a detailedoperation in each of the steps is as shown in Embodiment 1, Embodiment2, or Embodiment 3, the explanation of the detailed operation will beomitted hereafter. A low-capability terminal carries out an operation asexplained in Embodiment 1, Embodiment 2, or Embodiment 3. By using thismethod, while a paging signal sending method of sending a paging signalto a low-capability terminal currently receiving an MBMS service in anMBMS transmission dedicated cell is established, a sending method ofsending a paging signal to a high-capability terminal currentlyreceiving an MBMS service in an MBMS transmission dedicated cell can beconfigured in a general way to send paging signals to a high-capabilityterminal. As a result, when a high-capability terminal is receiving anMBMS service in a frequency layer dedicated to MBMS transmission, theprocess carried out by the mobile terminal and the process carried outby the mobile communication system can be simplified. The simplificationof the process can provide an advantage of achieving low powerconsumption in the mobile terminal. Furthermore, because the mobilecommunication system does not have to make a base station in an MBSFNarea transmit a paging signal to a high-capability terminal, there canbe provided an advantage of making effective use of the radio resources.

Furthermore, even a high-capability terminal carries out an operation asexplained in Embodiment 1, Embodiment 2, or Embodiment 3 according to auser's intention in order to prevent an increase in its powerconsumption at the time when carrying out a receiving operation ofreceiving a signal from an MBMS/Unicast-mixed cell, and a receivingoperation of receiving a signal from an MBMS transmission dedicated cellin parallel. As a result, even a high-capability terminal does not haveto carry out the receiving operations in parallel, and therefore therecan be provided an advantage of preventing an increase in its powerconsumption. The user's intention, as well as the mobile terminal pagingreception capability, are informed, in step ST1710, from the mobileterminal to the network side, and the subsequent processes carried outby the mobile communication system including the subsequent processescarried out by the mobile terminal are the same as those shown inEmbodiment 2.

Next, a variant will be explained. Nonpatent reference 8 discloses arelease indicator (Release indicator) as one parameter of the capabilityof a mobile terminal. However, nonpatent reference 8 does not describeany variation in the operation of a mobile communication system due to avariation in the release indicator. In this variant, a method ofswitching between sending methods each of sending a paging signal to amobile terminal currently receiving an MBMS service in an MBMStransmission dedicated cell according to the capability of the mobileterminal, concretely according to a release indicator which is oneparameter of the capability of the mobile terminal is disclosed.Furthermore, each mobile terminal uses, as the receiving method ofreceiving a paging signal while receiving an MBMS service, a receivingmethod of receiving a paging signal according to the capability of themobile terminal itself, concretely according to a release with which themobile terminal complies. In order to switch between the sending methodseach of sending a paging signal to a mobile terminal according to therelease with which the mobile terminal complies, information about thecapability of the mobile terminal needs to be shared among the mobileterminal, the serving base station, and the network side. To this end,in this variant, the capability (Capability) of the mobile terminal isinformed from the mobile terminal to the serving base station, and isfurther informed from the serving base station to the MME. As anexample, this capability (Capability) of the mobile terminal isinformed, in step ST1710, from the mobile terminal to the serving basestation, and is further informed, in step ST1712, from the serving basestation to the MME. As a result, the network side can recognize thepaging reception capability of the mobile terminal in question.Therefore, it becomes able to switch between the sending methods each ofsending a paging signal to a mobile terminal currently receiving an MBMSservice in a frequency layer dedicated to MBMS transmission according tothe paging reception capability of the mobile terminal.

Examples of the switching between the sending methods each of sending apaging signal will be disclosed. An example of the switching includes: astep (1) of using, as the sending method of sending a paging signal to amobile terminal currently receiving an MBMS service from an MBMSdedicated cell, the method shown in any of Embodiments 1 to 3 to send apaging signal from an MBMS dedicated cell to the mobile terminal, and astep (2) of using, as the sending method of sending a paging signal to amobile terminal currently receiving an MBMS service from an MBMSdedicated cell, a conventional sending method to send a paging signalfrom a unicast cell or an MBMS/Unicast-mixed cell to the mobileterminal. Another example of the switching includes: a step (1) ofusing, as the sending method of sending a paging signal to a mobileterminal currently receiving an MBMS service from an MBMS dedicatedcell, the method shown in any of Embodiments 1 to 3 to send a pagingsignal from an MBMS dedicated cell to the mobile terminal, and a step(2) of not sending any paging signal to a mobile terminal currentlyreceiving an MBMS service from an MBMS dedicated cell. Examples of theswitching between the sending methods each of sending a paging signalaccording to a release indicator will be disclosed. There can beconsidered a case in which whether a mobile terminal can receive apaging signal from an MBMS dedicated cell is determined according to arelease with which the mobile terminal complies. For example, a release8-compliant mobile terminal cannot receive a paging signal from an MBMSdedicated cell, while a release 9-compliant mobile terminal can receivea paging signal from an MBMS dedicated cell.

An example of the switching according to a release indicator includes: astep (1) of, when a release-compliant mobile terminal which can receivea paging signal from an MBMS dedicated cell is receiving an MBMS servicefrom an MBMS dedicated cell, using, as the sending method of sending apaging signal to a mobile terminal, the method shown in any ofEmbodiments 1 to 3 to send a paging signal from the MBMS dedicated cellto the release-compliant mobile terminal, and a step (2) of, when arelease-compliant mobile terminal which cannot receive a paging signalfrom an MBMS dedicated cell is receiving an MBMS service from an MBMSdedicated cell, using, as the sending method of sending a paging signalto a mobile terminal, a conventional sending method to send a pagingsignal from a unicast cell or an MBMS/Unicast-mixed cell to therelease-compliant mobile terminal. Another example of the switchingaccording to a release indicator includes: a step (1) of, when arelease-compliant mobile terminal which can receive a paging signal froman MBMS dedicated cell is receiving an MBMS service from an MBMSdedicated cell, using, as the sending method of sending a paging signalto a mobile terminal, the method shown in any of Embodiments 1 to 3 tosend a paging signal from the MBMS dedicated cell to therelease-compliant mobile terminal, and a step (2) of, when arelease-compliant mobile terminal which cannot receive a paging signalfrom an MBMS dedicated cell is receiving an MBMS service from an MBMSdedicated cell, not transmitting a paging signal destined for therelease-compliant mobile terminal to the release-compliant mobileterminal.

In accordance with variant 1, the mobile communication system can switchbetween its operations by using conventional parameters withoutincreasing parameters to be informed from each mobile terminal to thenetwork side. As a result, there can be provided an advantage of makingeffective use of the radio resources. Furthermore, because the mobilecommunication system does not have to transmit a paging signal from anMBMS dedicated cell to a mobile terminal which cannot receive the pagingsignal from the MBMS dedicated cell, there can be provided an advantageof making effective use of the radio resources. As a result, there canbe provided an advantage of reducing the load on the network side.

Next, another variant will be explained as variant 2. Nonpatentreference 8 discloses MBMS-related parameters (MBMS Related parameters)as one parameter of the capability of a mobile terminal. However,nonpatent reference 8 does not disclose any descriptions of theMBMS-related parameters at all. In this variant, a method of switchingbetween sending methods each of sending a paging signal to a mobileterminal currently receiving an MBMS service in an MBMS transmissiondedicated cell according to the capability of the mobile terminal,concretely according to the MBMS-related parameters which are oneparameter of the capability of the mobile terminal is disclosed.Furthermore, each mobile terminal uses, as the receiving method ofreceiving a paging signal destined for the mobile terminal whilereceiving an MBMS service, a receiving method of receiving a pagingsignal according to the capability of the mobile terminal itself,concretely according to the MBMS-related parameters. In order to switchbetween the sending methods each of sending a paging signal to a mobileterminal according to the release with which the mobile terminalcomplies, information about the capability of the mobile terminal needsto be shared among the mobile terminal, the serving base station, andthe network side. To this end, in this variant, the capability(Capability) of the mobile terminal is informed from the mobile terminalto the serving base station, and is further informed from the servingbase station to the MME. As an example, this capability (Capability) ofthe mobile terminal is informed, in step ST1710, from the mobileterminal to the serving base station, and is further informed, in stepST1712, from the serving base station to the MME. As a result, thenetwork side can recognize the paging reception capability of the mobileterminal in question. Therefore, it becomes able to switch between thesending methods each of sending a paging signal to a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBMS transmission according to the paging reception capability of themobile terminal. Because examples of the switching between the sendingmethods each of sending a paging signal are the same as those of variant1, the explanation of the examples will be omitted hereafter. An exampleof the MBMS-related parameters, and an example of the switching betweenthe sending methods each of sending a paging signal according to theparameters will be disclosed.

An example of the parameters will be disclosed. In the MBMS-relatedparameters, a “low-capability terminal (or single-receiver-equippedterminal)” parameter and a “high-capability terminal (ortwo-receivers-equipped terminal)” parameter are provided. An example ofthe switching according to the parameters includes: a step (1) of, whena low-capability mobile terminal is receiving an MBMS service from anMBMS dedicated cell, using, as the sending method of sending a pagingsignal to a mobile terminal, the method shown in any of Embodiments 1 to3 to send a paging signal from the MBMS dedicated cell to thelow-capability mobile terminal, and a step (2) of, when ahigh-capability mobile terminal is receiving an MBMS service from anMBMS dedicated cell, using, as the sending method of sending a pagingsignal to a mobile terminal, a conventional sending method to send apaging signal from a unicast cell or an MBMS/Unicast-mixed cell to thehigh-capability mobile terminal. Another example of the switchingaccording to the parameters includes: a step (1) of, when ahigh-capability mobile terminal is receiving an MBMS service from anMBMS dedicated cell, using, as the sending method of sending a pagingsignal to a mobile terminal, a conventional sending method to send apaging signal from a unicast cell or an MBMS/Unicast-mixed cell to thehigh-capability mobile terminal, and a step (2) of, when alow-capability mobile terminal is receiving an MBMS service from an MBMSdedicated cell, not sending any paging signal to the low-capabilitymobile terminal. Another example of the parameters will be disclosed. Inthe MBMS-related parameters, an “MBMS-dedicated-cell-originated pagingsignal receivable” parameter and an “MBMS-dedicated-cell-originatedpaging signal unreceivable” parameter are disposed.

An example of the switching according to the parameters includes: a step(1) of, when a mobile terminal which can receive a paging signal from anMBMS dedicated cell is receiving an MBMS service from an MBMS dedicatedcell, using, as the sending method of sending a paging signal to amobile terminal, the method shown in any of Embodiments 1 to 3 to send apaging signal from the MBMS dedicated cell to the mobile terminal, and astep (2) of, when a mobile terminal which cannot receive a paging signalfrom an MBMS dedicated cell is receiving an MBMS service from an MBMSdedicated cell, using, as the sending method of sending a paging signalto a mobile terminal, a conventional sending method to send a pagingsignal from a unicast cell or an MBMS/Unicast-mixed cell to the mobileterminal. Another example of the switching according to the parametersincludes: a step (1) of, when a mobile terminal which can receive apaging signal from an MBMS dedicated cell is receiving an MBMS servicefrom an MBMS dedicated cell, using, as the sending method of sending apaging signal to a mobile terminal, the method shown in any ofEmbodiments 1 to 3 to send a paging signal from the MBMS dedicated cellto the mobile terminal, and a step (2) of, when a mobile terminal whichcannot receive a paging signal from an MBMS dedicated cell is receivingan MBMS service from an MBMS dedicated cell, not sending any pagingsignal to the mobile terminal.

In accordance with variant 2, the mobile communication system can switchbetween its operations by using conventional parameters withoutincreasing parameters to be informed from each mobile terminal to thenetwork side. As a result, there can be provided an advantage of makingeffective use of the radio resources. Furthermore, because the mobilecommunication system does not have to transmit a paging signal from anMBMS dedicated cell to a mobile terminal which cannot receive the pagingsignal from the MBMS dedicated cell and a mobile terminal which does nothave to receive the paging signal from the MBMS dedicated cell, therecan be provided an advantage of making effective use of the radioresources. As a result, there can also be provided an advantage ofreducing the load on the network side.

Embodiment 5

The sending method of sending a paging signal to a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBMS transmission is described in Embodiment 1, Embodiment 2, andEmbodiment 3. In this Embodiment 5, a method of enabling a user toselect “does not receive paging” according to the user's intention whilehis or her mobile terminal is receiving an MBMS service in a frequencylayer dedicated to MBMS transmission is disclosed. A concrete example ofthe operation of the mobile terminal at the time of selecting “does notreceive paging” according to the user's intention will be explained withreference to FIGS. 16 and 17. The mobile terminal which has selected“does not receive paging” according to the user's intention, in stepST1606, more specifically in a notification of the MBMS side receivingstate of step ST1742, informs that it “does not receive paging”.

Furthermore, the “notification of the MBMS receiving state” of stepST1742 can be made like in the case of an “attach request” shown inST1710, or as a type of “attach request”. As an alternative, the“notification of the MBMS receiving state” can be made like in the caseof “tracking area update (Tracking Area Update: TAU)”, or as a type of“tracking area update”. Parameters to be notified in this case includesan identifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal,the frequency (f(MBMS)) at which the mobile terminal ends the receptionof the MBMS service, the MBSFN area number (ID), the information showingthat the mobile terminal does not receive paging, like in theabove-mentioned case. As a result, the network side is enabled to knowthat the mobile terminal has ended the reception of the MBMS in the MBMSdedicated cell without adding any new message. Therefore, there can beprovided an advantage of being able to avoid the complexity of themobile communication system. Information showing that the “tracking areaupdate” includes the “notification of the MBMS receiving state” can beincluded in the “tracking area update”. As a concrete method, the“notification of the MBMS receiving state” can be added to the type(TYPE) information of TAU. The type information can be expressed as anumerical value. A 1-bit indicator showing whether or not to aim to makethe “notification of the MBMS receiving state” is formed on the TAUrequest message.

Information showing that the “attach request” message includes the“notification of the MBMS receiving state” can be included in the“attach request” message. As a concrete method, the “notification of theMBMS receiving state” can be added to the type information of the attachrequest. The type information can be expressed as a numerical value. A1-bit indicator showing whether or not to aim to make the “notificationof the MBMS receiving state” is formed on the attach request message. Asa result, in the former case, the conventional “tracking area update”can be distinguished from the “tracking area update” used in order tomake the “notification of the MBMS receiving state”. Furthermore, in thelatter case, the conventional “attach request” can be distinguished fromthe “attach request” used in order to make the “notification of the MBMSreceiving state”. As a result, there can be provided an advantage ofpreventing control delay from occurring in the mobile communicationsystem. Furthermore, the “notification of the MBMS receivingstate+information showing that the mobile terminal does not receivepaging” of step ST1828 can be made like in the case of an “attachrequest” shown in ST1710, or as a type of “attach request”. As analternative, the “notification of the MBMS receiving state+informationshowing that the mobile terminal does not receive paging” can be madelike in the case of “tracking area update (Tracking Area Update: TAU)”,or as a type of “tracking area update”.

Parameters to be notified in this case includes an identifier (UE-ID,IMSI, S-TMSI, or the like) of the mobile terminal, the frequency(f(MBMS)) at which the mobile terminal ends the reception of the MBMSservice, and the MBSFN area number (ID), like in the above-mentionedcase. As a result, the network side is enabled to know that the mobileterminal has ended the reception of the MBMS in the MBMS dedicated cellwithout adding any new message. Therefore, there can be provided anadvantage of being able to avoid the complexity of the mobilecommunication system. Information showing that the “tracking areaupdate” includes the “notification of the MBMS receivingstate+information showing that the mobile terminal does not receivepaging” can be included in the “tracking area update”. As a concretemethod, the “notification of the MBMS receiving state+informationshowing that the mobile terminal does not receive paging” can be addedto the type (TYPE) information of TAU. The type information can beexpressed as a numerical value. A 1-bit indicator showing whether or notto aim to make the “notification of the MBMS receiving state+informationshowing that the mobile terminal does not receive paging” is formed onthe TAU request message. Information showing that the “attach request”message includes the “notification of the MBMS receivingstate+information showing that the mobile terminal does not receivepaging” can be included in the “attach request” message. As a concretemethod, the “notification of the MBMS receiving state+informationshowing that the mobile terminal does not receive paging” can be addedto the type information of the attach request. The type information canbe expressed as a numerical value. A 1-bit indicator showing whether ornot to aim to make the “notification of the MBMS receivingstate+information showing that the mobile terminal does not receivepaging” is formed on the attach request message. As a result, in theformer case, the conventional “tracking area update” can bedistinguished from the “tracking area update” used in order to make the“notification of the MBMS receiving state+information showing that themobile terminal does not receive paging”. Furthermore, in the lattercase, the conventional “attach request” can be distinguished from the“attach request” used in order to make the “notification of the MBMSreceiving state+information showing that the mobile terminal does notreceive paging”. As a result, there can be provided an advantage ofpreventing a control delay time from occurring in the mobilecommunication system.

The mobile terminal does not carry out steps ST1605, ST1608, ST1610, andST1611. The simplification of the process carried out by the mobileterminal can provide an advantage of achieving low power consumption inthe mobile terminal. The mobile communication system, in step ST1745,receives the information showing that the mobile terminal in question“does not receive paging”. In step ST1746, information showing “stop ofnotification of paging” to the mobile terminal in question is stored inthe TA list of the mobile terminal in question or independently from theTA list. After that, paging to the mobile terminal in question occurs instep ST1773. The MME in which paging has occurred, in step ST1774,checks the tracking area list of the mobile terminal in question on thebasis of an identifier (UE-ID, IMSI, S-TMSI, or the like) of the mobileterminal in question for which the paging is destined. The MME thenchecks the “stop of notification of paging” to the mobile terminal inquestion. Also in this Embodiment, like in the case of Embodiment 2, themethod of including, as identifiers of each mobile terminal, a mobileterminal identifier used in a unicast/mixed frequency layer and a mobileterminal identifier used in a frequency layer dedicated to MBSFNtransmission can be used.

The mobile communication system stops a paging generation process ofsteps ST1775 to ST1783 and ST1814 to ST1818. The MME then informs“paging reception rejection” of the mobile terminal in question to thenetwork side. Accordingly, the mobile communication system can stop thepaging generation process for the mobile terminal which “does notreceive paging” according to the user's intention. As a result, there isprovided an advantage of being able to reduce the processing load on themobile communication system which is used for a notification of a pagingsignal which a mobile terminal does not intend to receive, and to reducethe radio resources.

Embodiment 6

In accordance with Embodiments 1 to 4, a mobile terminal is configuredin such a way as to carry out discontinuous reception again in anMBMS/Unicast-mixed cell (referred to as two-step discontinuous receptionfrom here on) even when receiving a paging signal destined for themobile terminal itself in a frequency layer dedicated to MBMStransmission. A base station in an MBMS transmission dedicated cell anda base station in an MBMS/Unicast-mixed cell are asynchronous to eachother in principle. Therefore, the two-step discontinuous reception iscarried out in order to solve a problem that a base station in an MBMStransmission dedicated cell cannot carry out allocation of radioresources for a downlink control signal after a base station has sentout a paging signal in an MBMS/Unicast-mixed cell. However, the two-stepdiscontinuous reception has a problem that the control delay becomeslarger than that in the case of a general configuration of sendingpaging signals to a mobile terminal other than a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBMS transmission. A concrete example of operation will be explainedwith reference to FIG. 17. A unicast cell or a mixed cell, in stepST1705, informs two different discontinuous reception cycle lengths byusing the BCCH. Concretely, they are the one for two-step discontinuousreception, and the one for typical discontinuous reception. Moreconcretely, the discontinuous reception cycle length for two-stepdiscontinuous reception is equal to or shorter than that for typicaldiscontinuous reception. The discontinuous reception period for two-stepdiscontinuous reception can represent continuous reception. Accordingly,the discontinuous reception period for two-step discontinuous receptionand that for typical discontinuous reception can be set to havedifferent lengths. As a result, there can be provided an advantage ofbeing able to configure the mobile communication system in such a way asto have high flexibility. There can be provided a further advantage ofbeing able to, even in a case in which a mobile terminal receives apaging signal destined therefor in a frequency layer dedicated to MBMStransmission, reduce the control delay by making the discontinuousreception cycle length for two-step discontinuous reception be equal toor shorter than that for typical discontinuous reception to enable themobile terminal to carry out discontinuous reception again in anMBMS/Unicast-mixed cell with the discontinuous reception cycle lengthbeing reduced.

Embodiment 7

It has been examined that an MBMS dedicated cell is newly disposed in anLTE system. This MBMS dedicated cell does not provide any unicastservice for carrying out dedicated communications destined for eachterminal. Therefore, it is difficult to apply a method executed in aW-CDMA system which can carry out both an MBMS service and a unicastservice, and which is defined by, for example, the release 6 standardsof the 3GPP to the MBMS dedicated cell, just as it is. It is necessaryto dispose a new paging channel in order for a mobile terminal toreceive paging from an MBMS dedicated cell. The present inventionprovides a method of enabling a mobile terminal which is receiving ortrying to receive an MBMS service in a frequency layer dedicated to MBMStransmission to receive a paging signal from an MBMS dedicated cell. Thepresent invention also discloses the structure of a channel and amapping method used for transmitting a paging signal, and a mobilecommunication system which has the channel and enables the method to beimplemented therein.

Hereafter, a method of carrying a paging signal on a physical multicastchannel (Physical multicast channel: PMCH) will be disclosed. FIG. 39 isan explanatory drawing showing the structure of a physical multicastchannel disposed for each MBSFN (Multimedia Broadcast multicast serviceSingle Frequency Network) area. In FIG. 39, time division multiplexing(Time Division Multiplexing: TDM) of the PMCHs of MBSFN areas 1 to 3onto each of which a multicast control channel (Multicast controlchannel: MCCH) and a multicast traffic channel (Multicast Trafficchannel: MTCH), which are downlink logical channels, are mapped iscarried out. Furthermore, in FIG. 39, a cell #n1 is one located in theMBSFN area 1, a cell #n2 is one located in the MBSFN area 2, and a cell#n3 is one located in the MBSFN area 3. Because the cell #n1 belongs tothe MBSFN area 1, the PMCH corresponding to the MBSFN area istransmitted at a time. Because the PMCH is transmitted via a multi-cell(Multi Cell: MC) transmission scheme in the MBSFN area, the PMCH istransmitted on MBSFN subframes. A set of MBSFN frames to which the MBSFNsubframes are allocated is referred to as an “MBSFN frame cluster”(MBSFN frame cluster). In the MBMS dedicated cell, all subframes in anMBSFN frame can be the MBSFN subframes used for multi-cell transmission.The length of each of the repetition periods at which the MBSFN framecluster is repeated is expressed as the “MBSFN frame cluster repetitionperiod” (MBSFN frame cluster Repetition period).

An MCH which is a transport channel for one or more MBMS services ismapped onto the PMCH, and either or both of the MCCH which is a logicalchannel for MBMS control information and the MTCH which is a logicalchannel for MBMS data are mapped onto the MCH. The MCCH and the MICH canbe divided in time and mapped onto the PMCH, and can be further dividedin time and mapped onto a physical area which is transmitted via amulti-cell transmission scheme. For example, the MCCH and the MTCH canbe mapped onto different MBSFN subframes which are the physical areaonto which they are mapped. The MCCH can be mapped onto each MBSFN framecluster, or only the MTCH can be mapped onto each MBSFN frame cluster.In a case in which only the MTCH is mapped onto the PMCH, the repetitionperiod of the MCCH differs from the repetition period of the MBSFN framecluster. Furthermore, there is a case in which a plurality of MCCHs aremapped onto each MBSFN frame cluster. The length of each of therepetition periods at which the MCCH is repeated is expressed as the“MCCH repetition period” (MCCH Repetition period). In FIG. 39, MCCH1 isMBMS control information for the MBSFN area 1, and MTCH1 is MBMS datafor the MBSFN area 1. The cell #n2 belongs to the MBSFN area 2, MCCH2 isMBMS control information for the MBSFN area 2, and MTCH2 is MBMS datafor the MBSFN area 2. The cell #n3 belongs to the MBSFN area 3, MCCH3 isMBMS control information for the MBSFN area 3, and MTCH3 is MBMS datafor the MBSFN area 3. The repetition period of the MCCH can differ foreach MBSFN area. Time division multiplexing of the PMCHs of the MBSFNareas is carried out. Therefore, the orthogonality among the cells ofthe MBSFN areas is acquired in the MBSFN synchronization area (refer tothe MBSFN Synchronization Area as shown in FIG. 7) in which thesynchronization among the cells is ensured, and the interference from acell in another MBSFN area can be prevented. Because the PMCH istransmitted via a multi-cell transmission scheme in each MBSFN area,each cell in each MBSFN area transmits the same data by using the samePMCH. Because, even if one cell belongs to a plurality of MBSFN areasand two or more cells overlap one another, time division multiplexing ofthe PMCHs of the MBSFN areas is carried out and they are transmitted onMBSFN subframes, the above-mentioned PMCH configuration can be appliedwith the orthogonality among the MBSFN areas being maintained.

Therefore, a mobile terminal can receive an MBMS service by receivingPMCHs which are transmitted via a multi-cell transmission scheme from aplurality of cells in an MBSFN area in which the mobile terminal itselfis being located, and can improve its quality of reception with an SFNgain obtained from the multi-cell transmission. Even in a case in whichone cell belongs to a plurality of MBSFN areas, the mobile terminal canreceive a plurality of MBMS services by receiving the PMCH of each ofthe MBSFN areas. Furthermore, a mobile terminal currently receiving thePMCH of a certain desired MBSFN area can carry out a discontinuousreception (Discontinuous Reception: DRX) operation during a time periodother than the time of receiving this PMCH because the mobile terminaldoes not have to receive any PMCH other than the above-mentioned PMCH,and can therefore reduce its power consumption. Because the mobileterminal can carry out the discontinuous reception operationcontinuously in a case in which the PMCH is transmitted continuously ineach MBSFN area with the MBSFN frames being handled as an MBSFN framecluster, the mobile terminal can further reduce its power consumption.

FIG. 40 is an explanatory drawing showing the structure of a physicalmulticast channel disposed for each MBSFN (Multimedia Broadcastmulticast service Single Frequency Network) area. In FIG. 39, timedivision multiplexing (Time Division Multiplexing: TDM) of the PMCHs inthe MBSFN areas 1 to 3 is carried out. A case in which code divisionmultiplexing (Code Division Multiplexing: CDM) of the PMCHs in the MBSFNareas 1 to 3 is carried out is shown in FIG. 40. A cell #n1 is onelocated in the MBSFN area 1, a cell #n2 is one located in the MBSFN area2, and a cell #n3 is one located in the MBSFN area 3. In the cell #n1,the PMCH corresponding to the MBSFN area 1 is transmitted. In this case,this PMCH can be continuous or discontinuous in time. In a case in whichthe PMCH is discontinuous in time, the length of each of the repetitionperiods at which the MBSFN frame cluster via which the PMCHcorresponding to the MBSFN area is transmitted is repeated becomes equalto the length of the “MBSFN frame cluster repetition period” (MBSFNframe cluster Repetition period). In contrast, in a case in which thePMCH is continuous in time, the MBSFN frame cluster repetition periodcan be expressed as 0 or it is not necessary to specify this repetitionperiod. The MCCH and the MTCH can be divided in time and mapped onto thePMCH, and can be further divided in time and mapped onto a physical areawhich is transmitted via a multi-cell transmission scheme. For example,the MCCH and the MTCH can be mapped onto different MBSFN subframes whichare the physical area onto which they are mapped as a result. The lengthof each of the repetition periods at which the MCCH is repeated isexpressed as the “MCCH repetition period” (MCCH Repetition period).Similarly, the PMCH corresponding to the MBSFN area 2 is transmitted inthe cell #n2, and the PMCH corresponding to the MBSFN area 3 istransmitted in the cell #n3. The repetition period of the MCCH candiffer in each of the MBSFN areas. Because data which is multiplied bythe MBSFN-area-specific scrambling code is mapped onto the PMCH in eachof the MBSFN areas, the interference among the MBSFN areas in the MBSFNsynchronization area in which the synchronization among the cells isensured can be suppressed. Because the multi-cell transmission is usedin each of the MBSFN areas, each cell in each of the MBSFN areastransmits the same data, i.e., the data which is multiplied by theMBSFN-area-specific scrambling code (Scrambling Code) with the samePMCH. Even in a case in which one cell belongs to a plurality of MBSFNareas, the above-mentioned PMCH configuration can be applied with theinterference among the MBSFN areas being suppressed.

A mobile terminal receives the PMCHs which are transmitted via amulti-cell transmission scheme from a plurality of cells in the MBSFNarea in which the mobile terminal itself is being located, and carriesout descrambling (Descramble) by using the MBSFN-area-specificscrambling code. As a result, the mobile terminal can receive an MBMSservice while removing the influence of the interference from anotherMBSFN area, and can improve its quality of reception with an SFN gainobtained from the multi-cell transmission. Also in a case in which onecell belongs to a plurality of MBSFN areas, the mobile terminal canreceive a plurality of MBMS services by receiving the PMCH of each ofthe MBSFN areas and carrying out descrambling by using eachMBSFN-area-specific scrambling code. Furthermore, in a case in which thePMCH of a certain desired MBSFN area is discontinuous in time, themobile terminal can carry out a discontinuous reception operation duringa time period other than the time of receiving this PMCH, and cantherefore reduce its power consumption because the mobile terminal doesnot have to carry out the reception during the time period other thanthe time of receiving the above-mentioned PMCH. When two or moreservices to be mapped onto the PMCH exist and time domain multiplexingof these services on the PMCH is carried out even if the PMCH iscontinuous in time, the mobile terminal has only to receive a timesegment in this PMCH onto which a desired service is mapped, and doesnot have to receive any other time segments. Therefore, the mobileterminal can carry out a discontinuous reception operation duringanother time period within this PMCH, and can reduce its powerconsumption.

FIG. 32 is an explanatory drawing showing the structure of a physicalmulticast channel (PMCH) onto which a paging signal is mapped. Thestructure of the physical multicast channel (PMCH) onto which a pagingsignal is mapped is shown in FIG. 32. FIG. 32(a) is a view showing thePMCH in which an area used for paging signal is disposed, and shows thatMBMS-related information and the paging signal are included on the PMCH.The MBMS-related information and the paging signal can exist asinformation elements in an MTCH and an MCCH respectively, ortime-division multiplexing of physical areas (resources) onto which theMBMS-related information and the paging signal are mapped respectivelycan be carried out. FIG. 53 is an explanatory drawing showing a mappingmethod in a case of carrying, as information elements, the MBMS-relatedinformation and the paging signal onto the multicast control channel(MCCH). MBMS control information included in the MBMS-relatedinformation as well as the paging signal are mapped on the logicalchannel MCCH. The MCCH as well as the MTCH are mapped onto a multicastchannel (MCH) which is a transport channel, and the MCH is mapped ontothe physical multicast channel (PMCH) which is a physical channel. Thus,a mobile terminal which is receiving or trying to receive an MBMSservice is enabled to receive the paging information when receiving theMCCH.

Another example will be explained. FIG. 54 is an explanatory drawingshowing a mapping method in a case of multiplexing a logical channelPCCH and the logical channels MTCH and MCCH to carry them on thetransport channel MCH. In FIG. 54, the paging signal is mapped onto thelogical channel PCCH, and the MBMS-related information is mapped ontothe MTCH and the MCCH. A base station can provide an MBSFN subframe ontowhich only the MTCH is mapped, and an MBSFN subframe onto which the MCCHand the PCCH are mapped. The base station can also control to provide anMBSFN subframe onto which only the MCCH is mapped, and an MBSFN subframeonto which only the PCCH is mapped. By doing in this way, the basestation can transmit the MTCH and, the MCCH and PCCH separately in timefrom each other, and can further transmit the MCCH and the PCCHseparately in time from each other. The mobile terminal has only toreceive an MBSFN subframe including necessary information, and cantherefore carry out a DRX operation during a time period during which itreceives an MBSFN subframe including unnecessary information.Furthermore, an MBSFN subframe onto which the MCCH is carried and anMBSFN subframe onto which the PCCH is mapped can be arranged in such away as to be adjacent to each other in time. For example, the basestation carries out scheduling in such a way that the MBSFN subframeonto which the PCCH is mapped is arranged successively after (or before)the MBSFN subframe onto which the MCCH is mapped. A mobile terminalwhich is receiving or trying to receive an MBMS can know the receivingtimes of receiving the MCCH and the PCCH respectively from the MCCHrepetition period length by making the MCCH and the PCCH be arrangedcontinuously in order to receive the MCCH. Therefore, a mobile terminalwhich is receiving or trying to receive an MBMS can receive the pagingsignal successively at the time of receiving the MCCH. Furthermore,because no MTCH is placed between the MCCH and the PCCH, when theterminal is not receiving the MTCH, the terminal can receive the PCCHwithout making a transition to a DRX operation. As another example, amethod of using the MCH and a PCH is shown in FIG. 55. FIG. 55 is anexplanatory drawing showing a mapping method in a case of carrying thelogical channel PCCH on the transport channel PCH, carrying outmultiplexing of the logical channels MTCH and MCCH to carry them on thetransport channel MCH, and further multiplexing the PCH and the MCH tocarry them onto the physical multicast channel. In FIG. 55, the pagingsignal is mapped onto the PCCH and this PCCH is mapped onto thetransport channel PCH. Multiplexing of this PCH and the MCH is carriedout, and they are mapped onto the PMCH. By doing in this way, the basestation can transmit the PCH and the MCH separately in time from eachother, and can further perform encoding on them independently from eachother. Therefore, the mobile terminal can decode each of the PCH and theMCH independently at the time of reception of them.

All the cells in a certain MBSFN area carry the MCCH corresponding tothis MBSFN area on the PMCH, and then carry out multi-cell transmissionperiodically at the MCCH repetition periods (MCCH repetition periods). Amobile terminal which is receiving or trying to receive an MBMS servicewhich is transmitted via a multi-cell transmission scheme from cells inthe above-mentioned MBSFN area receives the above-mentioned MCCH atregular intervals and also receives the contents of the MBMS service,information about the frame structure, etc., so that the mobile terminalcan receive the MBMS service. Therefore, as disclosed by FIG. 53, byincluding the paging signal in this MCCH, a mobile terminal which isreceiving or trying to receive an MBMS service is enabled to receive thepaging information when receiving the MCCH. As a result, because themobile terminal does not have to receive the paging separately at a timeother than the time of receiving the MCCH, the mobile terminal canreceive the paging without interrupting the reception of the MBMSservice. Furthermore, during a time period during which the mobileterminal is not receiving the MCCH, and during a time period duringwhich the mobile terminal is not receiving the MBMS service, the mobileterminal can carry out a discontinuous reception operation, therebybeing able to reduce its power consumption.

In the case of the mapping method disclosed in FIG. 54, the MCCH and thePCCH can be configured in such a way that they are disposed in anidentical MBSFN subframe, and an MBSFN subframe onto which the MCCH ismapped and an MBSFN subframe onto which the paging signal is mapped canbe separated from each other in time and can be arranged in such a wayas to be adjacent to each other in time. One feature of the presentinvention is that “a mobile terminal is enabled to, when seeing theMCCH, also see the PCCH”. Therefore, when the MCCH and the PCCH aremapped onto an identical MBSFN subframe, the mobile terminal has only toreceive the subframe, whereas when time division multiplexing of anMBSFN subframe onto which the MCCH is mapped and a subframe onto whichthe PCCH is mapped is carried out, it is preferable to make them beadjacent to each other. In the case of the mapping method disclosed inFIG. 55, what is necessary is just to make an MBSFN subframe onto whichthe MCCH is mapped, and an MBSFN subframe onto which the paging signalis mapped be adjacent in time to each other. For example, the basestation carries out scheduling in such a way that an MBSFN subframe ontowhich the PCCH is mapped is arranged successively after (or before) anMBSFN subframe onto which the MCCH is mapped. In the case in which theyare configured in this way, a mobile terminal which is receiving ortrying to receive an MBMS service is enabled to receive the pagingsignal continuously when receiving the MCCH. As a result, because themobile terminal does not have to separately receive the paging signal ata time other than the time of receiving the subframe onto which the MCCHand the PCCH are mapped, the mobile terminal can receive the pagingsignal without interrupting the reception of the MBMS service.Furthermore, during a time period during which the mobile terminal isnot receiving the MCCH, and during a time period during which the mobileterminal is not receiving the MBMS service, the mobile terminal cancarry out a discontinuous reception operation, thereby being able toreduce its power consumption.

The configuration of disposing an indicator indicating whether or notthe MBMS control information has been changed, and an indicatorindicating whether or not the paging signal has been transmitted isshown in FIG. 32(b). Either or both of these indicators can be disposed.The indicator indicating whether or not the MBMS control information hasbeen modified is referred to as the “MBMS-related information modifiedor unmodified indicator”, and the indicator indicating whether thepaging signal has been transmitted is referred to as the “paging signalpresence or absence indicator”. A physical area onto which theindicators are mapped can be disposed in an MBSFN subframe via which thePMCH is transmitted. As an alternative, a physical area onto which theindicators are mapped can be the one adjacent in time to the MBSFNsubframe via which the PMCH is transmitted. By configuring the physicalarea onto which the indicators are mapped in this way, each mobileterminal can receive and decode the MCCH and the paging signal which aremapped onto the PMCH immediately after receiving the indicators. Forexample, 1-bit information is defined as each of the indicators. Each ofthe indicators is multiplied by an MBSFN-area-specific scrambling codeor the like, and is mapped onto a predetermined physical area. Inaccordance with another method, for example, each of the indicators canbe formed of an MBSFN-area-specific sequence, and can be mapped onto apredetermined physical area. When an incoming call to a mobile terminalis occurring, the corresponding paging signal presence or absenceindicator is set to “1”, whereas when no incoming call to the mobileterminal is occurring, the paging signal presence or absence indicatoris set to “0”. Furthermore, for example, when the MBMS controlinformation which is mapped onto the MCCH has been changed due to achange in the contents of the MBMS service transmitted in the MBSFNarea, or the like, the MBMS-related information modified or unmodifiedindicator is set to “1”. The length of a time period (referred to as anMBMS modification period) during which the MBMS-related information canbe modified is determined, and the MBMS-related information modified orunmodified indicator “1” is transmitted repeatedly within this MBMSmodification period. This MBMS modification period length, the starttiming (the SFN and the starting point), etc. can be predetermined. Asan alternative, they can be informed via broadcast information fromeither the serving cell using a unicast service or the MBMS dedicatedcell. When there is no further modification in the MBMS-relatedinformation after the expiration of the MBMS modification period, theMBMS-related information modified or unmodified indicator is set to “0”.

The mobile terminal can determine whether or not there is a modificationin the MBMS-related information which exists in the MCCH and whether ornot the paging signal exists by receiving the indicators within eitheran MBSFN subframe via which the PMCH of a desired MBSFN area istransmitted via a multi-cell transmission scheme, or an adjacent MBSFNsubframe, and performing de-spreading and so on each of the indicatorsto determine whether or not each of the indicators is 1 or 0. By thusdisposing the indicators, when there is no modification in the MBMScontrol information and when no paging signal exists, the mobileterminal does not have to receive and/or decode all the information onthe PMCH. Therefore, it becomes able to reduce the power for receivingof the mobile terminal. The physical area onto which the MBMS-relatedinformation modified or unmodified indicator indicating whether the MBMScontrol information has been modified is mapped can be the first one ofone or more MBSFN subframes onto which the MBMS control information ismapped. As an alternative, the physical area onto which the MBMS-relatedinformation modified or unmodified indicator indicating whether the MBMScontrol information has been modified is mapped can be an OFDM(Orthogonal Frequency Division Multiplexing) symbol at the head of theabove-mentioned first MBSFN subframe. As a result, the mobile terminalbecomes able to determine whether a modification has occurred in theMBMS control information by receiving the first OFDM symbol.

Furthermore, the physical area onto which the paging signal presence orabsence indicator indicating whether or not the paging signal exists ismapped can be the first one of one or more MBSFN subframes onto whichthe paging signal is mapped. As an alternative, the physical area ontowhich the MBMS-related information modified or unmodified indicatorindicating whether the MBMS control information has been modified ismapped can be an OFDM symbol at the head of the above-mentioned firstMBSFN subframe. As a result, the mobile terminal becomes able todetermine whether or not the paging signal exists by receiving the firstOFDM symbol. By mapping each indicator onto such a physical area asmentioned above, when there is no modification in the MBMS controlinformation and when no paging signal exists, the mobile terminal doesnot have to receive and/or decode subsequent OFDM symbols. Therefore, itbecomes able to further reduce the power for receiving of the mobileterminal. Furthermore, because the mobile terminal can determine whetherthere is no modification in the MBMS control information or whether apaging signal exists at an earlier time from the first MBSFN subframe orthe OFDM symbol at the head of the first MBSFN subframe, the mobileterminal can receive the MBMS control information immediately or canreceive the paging signal immediately, it becomes able to reduce thecontrol delay in the mobile terminal. The MBMS-related informationmodified or unmodified indicator and the paging signal presence orabsence indicator can be mapped onto an identical physical area, or canbe mapped onto different physical areas. In the case in which theindicators are mapped onto an identical physical area, what is necessaryis just to implement an OR logical operation on the indicators. As aresult, each mobile terminal has only to receive a single indicator,there is provided an advantage of being able to simplify the receivingcircuit configuration. In contrast, in the case in which the indicatorsare mapped onto different physical areas, each mobile terminal has onlyto receive only a required one of the indicators without having toreceive the other indicator. Therefore, the power for receiving of themobile terminal can be further reduced, and the delay time occurring inthe reception of the required information can be further reduced. Forexample, when the mobile terminal is set so as not to receive a pagingsignal while receiving an MBMS service, the mobile terminal has only toreceive the MBMS-related information modified or unmodified indicator,and can therefore eliminate the necessity to receive the paging signalpresence or absence indicator. The lengths of the repetition periods ofthe indicators can be the same as each other, or can be different fromeach other. The length of the repetition period of each of theindicators can be the same as that of the MCCH, or can be different fromthat of the MCCH. For example, the MBMS-related information modified orunmodified indicator can be disposed in the PMCH onto which the MCCH ismapped once for every plural times the PMCH is transmitted.

The lengths of the repetition periods of the indicators are referred toas the paging signal presence or absence indicator repetition period(Repetition period) and the MBMS-related modified or unmodifiedindicator repetition period (Repetition period), respectively. The starttiming (the SFN and the starting point) of the MBSFN subframe in whichthe indicator exists, the subframe number, the repetition period lengthsof the indicators, and so on can be informed via broadcast informationfrom the serving cell using a unicast service, can be informed viabroadcast information from the MBMS dedicated cell, or can bepredetermined. The channel dedicated to the MBMS-related informationmodified or unmodified indicator can be an MICH (MBMS IndicatingCHannel), for example. Furthermore, the paging signal presence orabsence indicator can be formed in the MICH. The length of therepetition period of the paging signal presence or absence indicator canbe the same as that of the repetition period of the MICH (MICHRepetition period), or can be different from that of the MICH. Thenotification of the indicators can be made by using the same method asthat described previously. As a result, the time when each indicator istransmitted is not limited to the time when the MCCH is transmitted, andtherefore it becomes able to design the system with flexibility.

In a case in which the paging signal is included in the PMCH, therearises a problem that when the number of mobile terminals for each ofwhich an incoming call is occurring becomes huge, it takes too much timefor each mobile terminal to detect a paging signal destined for themobile terminal itself. A further problem is that any area onto whichthe paging signals for all the mobile terminals for each of which anincoming call is occurring are to be mapped cannot be ensured in acertain physical area onto which the paging signals are to be mapped. Inorder to solve these problems, a method of carrying out paging groupingwill be disclosed hereafter. The method of carrying out paging groupingis shown in FIG. 32(c). All the mobile terminals are divided into Kgroups, and a paging signal presence or absence indicator is disposedfor each of the groups. A physical area used for paging signal presenceor absence indicator is divided into K parts, and the paging signalpresence or absence indicators of the K groups are mapped onto the Kdivided parts of the physical area respectively. In this case, K canhave a value ranging from 1 to the number of all the mobile terminals.When an incoming call to a mobile terminal is occurring, the pagingsignal presence or absence indicator of the group to which this mobileterminal belongs is set to “1”. When no incoming call to any of all themobile terminals belonging to a group is occurring, the paging signalpresence or absence indicator of this group is set to “0”. A repetitionor the like of the same paging signal presence or absence indicatorvalue can be carried out so that each of corresponding mobile terminalssatisfies a desired error rate of reception. The physical area ontowhich paging signals are mapped is also divided into K parts, and theseK parts are brought into correspondence with the above-mentioned Kgroups respectively. As the paging signal destined for each mobileterminal, an identifier of the mobile terminal (an identification numberor an identification code) can be provided. Each of the K divided piecesof the physical area is the sum of the corresponding group's mobileterminals' physical areas in each of which paging signal data requiredby one mobile terminal is accommodated. The number of mobile terminalsin each group can be identical to that in any other group, or can bedifferent from that in any other group.

The number of mobile terminals in each group is calculated by using, forexample, a method of calculating the average of measurements of thenumber of mobile terminals for each of which an incoming call hasoccurred simultaneously. As an alternative, a method of defining thenumber of mobile terminals which can be allocated to one OFDM symbol asthe number of mobile terminals in each group, and then bringing aplurality of OFDM symbols into correspondence with the plurality ofgroups respectively can be used. When an incoming call to a mobileterminal is occurring, “1” is set to the paging signal presence orabsence indicator of the group to which this mobile terminal belongs,and the paging signal presence or absence indicator is mapped onto thephysical area corresponding to this group and used for the paging signalpresence or absence indicator. In addition, the paging signal destinedfor the mobile terminal for which an incoming call is occurring ismapped onto the physical area of the paging signal corresponding to thegroup to which this mobile terminal belongs. The mapping of the pagingsignal to the physical area is carried out by using a method ofmultiplying the paging signal destined for each mobile terminal by anidentification code specific to this mobile terminal. The paging signaldestined for each mobile terminal can be an identifier of the mobileterminal. In this case, the above-mentioned control operation ofmultiplying the paging signal destined for each mobile terminal by theidentification code specific to the mobile terminal can be omitted.

As the identification code specific to each mobile terminal, a codespecific to each cell is used when unicast transmission is performed. Aproblem is, however, that in a case in which themobile-terminal-specific identification code is specific to each cellhaving a frequency layer dedicated to MBMS, the same data is nottransmitted from each cell when MC transmission is carried out in anMBSFN area, and therefore each mobile terminal becomes unable to receivethe data from the serving cell because a transmission signal fromanother cell acts as noise and the quality of reception degrades. Inorder to solve this problem, in accordance with the present invention,the identification code specific to each mobile terminal is defined asto be specific to each MBSFN area. As a concrete example, the mobileterminal identification code is disposed for each MBSFN area, and thismobile terminal identification code is transmitted in advance to mobileterminals to each of which a paging signal can be transmitted from theMBSFN area. As an alternative, the mobile terminal identification codecan be derived from an IMSI or an MBSFN area ID. A method of derivingthe mobile terminal identification code can be predetermined. Thenetwork side and each mobile terminal side can derive the mobileterminal identification code by using an identical parameter and anidentical computation expression. Accordingly, it is not necessary totransmit the mobile terminal identification code specific to each MBSFNarea from the network side to each mobile terminal. Therefore, there isprovided an advantage of being able to reduce the amount of signaling.This mobile-terminal-specific identification code specific to each MBSFNarea can be broadcast as broadcast information from neither the unicastcell nor the MBMS dedicated cell because the mobile-terminal-specificidentification code is dedicated information. Therefore, what isnecessary is just to derive the mobile-terminal-specific identificationcode by using a mobile-terminal-specific number, such as an MBSFN areaID or an IMSI. What is necessary is to derive the mobile terminalidentification number specific to each MBSFN area by using an identicalcomputation expression in both the network side (an MME and an MCE) andeach mobile terminal. The computation expression can be predetermined.As a result, it becomes able to use the identification code specific toeach MBSFN area as this mobile-terminal-specific identification code,and therefore each mobile terminal becomes able to receive the pagingsignal destined for the mobile terminal itself.

In accordance with another method, the MME derives themobile-terminal-specific identification code specific to each MBSFN areaby using a specific identification number and the MBSFN area ID of eachmobile terminal, transmits the mobile-terminal-specific identificationcode to each mobile terminal via the serving cell, and further transmitsthe mobile-terminal-specific identification code to the MCE. Forexample, the MME transmits the mobile-terminal-specific identificationcode to each mobile terminal via the serving cell by using attach acceptas shown in steps ST1716 to ST1718. The method of transmitting themobile-terminal-specific identification code to each mobile terminal viathe serving cell is not limited to the use of the attach accept. Forexample, the MME can transmit the mobile-terminal-specificidentification code to each mobile terminal by using an dedicated signal(a DCCH, a DTCH, or the like). As an alternative, the MME can transmitthe mobile-terminal-specific identification code to each mobile terminalby using a paging request which the MME transmits to the MCE, forexample, in ST1776. The MCE can transmit the mobile-terminal-specificidentification code to the MBMS dedicated cell, together with the pagingrequest of ST1780. In this case, because the mobile-terminal-specificidentification code is transmitted together with the paging request,control operations performed by the MME, the MCE, and the MBMS dedicatedcell can be simplified. The MME is allowed to derive themobile-terminal-specific identification number defined for each MBSFNarea by using a specific identification number and the MBSFN area ID ofeach mobile terminal. The method of making the mobile terminalidentification code be specific to each MBSFN area is not appliedlimitedly to this embodiment. The method of making the mobile terminalidentification code be specific to each MBSFN area can also be appliedto a case of, when carrying out multi-cell (MC) transmission of data ineach MBSFN area, multiplying the data by the mobile-terminal-specificidentification code. Two or more mobile-terminal-specific identificationcodes specific to each mobile terminal can be defined for each MBSFNarea. The two or more mobile-terminal-specific identification codes canbe put to different uses. For example, two differentmobile-terminal-specific identification codes specific to each mobileterminal are provided for each MBSFN area, and one of them is used forthe paging signal and the other identification code is used for the MBMScontrol information. By providing two different mobile-terminal-specificidentification codes in this way, the paging signal which is transmittedvia an MC transmission scheme in the MBSFN area is separated into partsrespectively destined for mobile terminals and each of the mobileterminals can receive the paging signal destined for the mobile terminalitself.

Furthermore, the physical area onto which the indicator showing whetherthe paging signal has been transmitted (e.g., the paging signal presenceor absence indicator) is mapped can be an MBSFN subframe onto which thepaging signal is mapped. By thus defining an MBSFN subframe onto whichthe paging signal is mapped as the physical area onto which theindicator showing whether the paging signal has been transmitted ismapped, both of the information about the scheduling of the MBSFNsubframe in which the paging signal presence or absence indicator exists(e.g., the leading one of MBSFN frames, the length of the period of theMBSFN frames, etc.), and the information about the scheduling of theMBSFN subframe in which the paging signal exists do not have to benotified or predetermined, though only one of them can be notified orpredetermined. Therefore, it becomes able to simplify a controloperation of controlling the paging process, and there is providedanother advantage of being able to reduce the amount of signalingbetween the network side or the base station and each mobile terminal.

Each mobile terminal determines whether an incoming call destined forthe group to which the mobile terminal itself belongs is occurring byreceiving the paging signal presence or absence indicator of the groupto which the mobile terminal itself belongs. Each mobile terminalreceives and decodes (Decodes) the physical area onto which the pagingsignal brought into correspondence with the group onto which the mobileterminal belongs is mapped when determining that an incoming calldestined for the group to which the mobile terminal itself belongs isoccurring. After decoding the physical area, each mobile terminalcarries out an operation of calculating a correlation with theidentification code specific to the mobile terminal to carry out blinddetection to specify the paging signal destined for the mobile terminalitself. As a result, each mobile terminal becomes able to determine thatan incoming call to the mobile terminal itself is occurring. When eachmobile terminal has not detected the paging signal destined therefor,the mobile terminal determines that no incoming call thereto isoccurring. By grouping all the mobile terminals into the K groups, thenecessity for each of the mobile terminals to receive all of the areaused for paging signal can be eliminated, and each of the mobileterminals has only to receive only a required area, i.e., a physicalarea corresponding to the group to which the mobile terminal itselfbelongs. Therefore, the length of time required for each of the mobileterminals to detect the paging signal destined therefor can beshortened. Furthermore, because each of the mobile terminals does nothave to receive a physical area corresponding to any other group towhich the mobile terminal itself does not belong, the power forreceiving of each of the mobile terminals can be reduced. In addition,by using the paging signal presence or absence indicator correspondingto each group, also when there are many mobile terminals, the pagingsignal presence or absence indicators can be provided by using a smallamount of physical resources. Furthermore, each of the mobile terminalshas only to receive an area used for the paging signal as needed.Therefore, while the power for receiving of each of the mobile terminalscan be reduced, the control delay time can also be reduced because eachof the mobile terminals can make a transition to the next operationimmediately when it does not have to receive the paging signal.

In above-mentioned Embodiment, each of the K divided pieces of thephysical area onto which paging signals are mapped is the sum of thecorresponding group's mobile terminals' physical areas in each of whichpaging signal data required by one mobile terminal is accommodated.However, because the required physical area becomes very large and theoverhead for transmitting the MBMS service increases greatly as thenumber of mobile terminals becomes huge, the transmission rate of theMBMS service data decreases. In order to prevent this problem, thepaging signal destined for each of the mobile terminals is multiplied byan identification code specific to the mobile terminal itself. As aresult, because each of the mobile terminals becomes able to carry outblind detection of whether or not it is information destined for themobile terminal itself by using the identification code specific to themobile terminal, it becomes unnecessary to fix the physical area ontowhich the paging signal destined for each of the mobile terminals ismapped in advance. Therefore, there is no necessity to provide aphysical area used for the paging signals destined for all the mobileterminals, and a physical area which is large enough to map pagingsignals destined for a certain number of mobile terminals for each ofwhich an incoming call is predicted to actually occur has only to beprovided. As an example, there is a method of defining the average ofmeasurements of the number of mobile terminals for each of which anincoming call has occurred simultaneously as the number of mobileterminals to be included in each group. By using this method, it becomesable to use the limited amount of physical resources effectively.Furthermore, by using the above-mentioned method, the mobilecommunication system can flexibly deal with even a case in which thenumber of mobile terminals for each of which an incoming call isoccurring becomes larger than a predicted number through scheduling inthe base station. For example, the mobile communication system cantransmit a paging signal destined for a mobile terminal currentlyreceiving a new incoming call on the next PMCH.

When the number of all the mobile terminals is small, only the pagingsignal presence or absence indicators can be transmitted by setting thevalue of K to be equal to the number of all the mobile terminals. Inthis case, there is no necessity to ensure any paging-related physicalarea, and what is necessary is just to ensure the physical area used forthe paging signal presence or absence indicators and corresponding tothe number of all the mobile terminals. Therefore, the efficiency of theradio resources can be improved. Furthermore, in this case, there existsa physical area used for a paging signal presence or absence indicatorand corresponding to each mobile terminal. Therefore, each of the mobileterminals can determine the presence or absence of an incoming callwithout receiving the area used for the paging signal by simplyreceiving and decoding the physical area used for the paging signalpresence or absence indicator and corresponding to the mobile terminalitself, thereby being able to reduce the control delay time occurringwhen performing the paging operation.

FIG. 33 is an explanatory drawing showing a method of mapping a pagingsignal onto an area on a physical multicast channel. In FIG. 33, pagingsignals destined for mobile terminals n1, n2, and so on for each ofwhich an incoming call, such as a voice call, is occurring, among mobileterminals belonging to a paging group n, are mapped onto a physical areacorresponding to this group n. The base station multiplies the pagingsignal destined for each of the mobile terminals by an identificationcode specific to this mobile terminal (a number or a sequence), carriesout CRC (Cyclic Redundancy Check) addition, and carries out a processincluding encoding (Encode) and rate matching. The result of the seriesof processes carried out is allocated to control channel elements (CCEs:Control Channel Elements) each having a size corresponding to the sizeof the physical area onto which the paging signals are mapped, and aplurality of control channel elements whose number is equal to that ofthe mobile terminals for each of which an incoming call is occurring areconnected to one another. The connected result is subjected to ascrambling process using an MBSFN-area-specific scrambling code(Scrambling code), a modulation process, etc. The modulation process canbe specific to the MBSFN area. The result of carrying out theseprocesses is mapped onto the physical area corresponding to the paginggroup n. In this case, the base station sets “1” to the paging signalpresence or absence indicator (indicator 1) of the paging group n, andthen maps it onto the physical area corresponding to the paging group nof the paging signal presence or absence indicator.

The physical area corresponding to the paging group n can bepredetermined, or can be informed, as broadcast information, from eitherthe unicast side serving cell or the MBMS dedicated cell to the basestation. Each of the mobile terminals receives the paging signalpresence or absence indicator of the paging group to which the mobileterminal itself belongs, and, when the paging signal presence or absenceindicator has a value of “1”, receives the physical area used for thepaging signal corresponding to this paging group. Each of the mobileterminals receives the physical area used for the paging signal, carriesout demodulation and descrambling (Descramble) using theMBSFN-area-specific scrambling code, and divides the result of thedemodulation and descrambling into parts each corresponding to a controlinformation element unit. Each of the mobile terminals carries out blinddetection of the paging signal destined for the mobile terminal itselfby performing a process including decoding (Decode) on each of thedivided parts each corresponding to a control information element unit,and then carries out an operation of calculating a correlation with themobile-terminal-specific identification number. When the result of thecorrelation operation is larger than a certain threshold, each of themobile terminals determines that there is paging destined for the mobileterminal itself, and starts an operation of receiving a paging incomingcall with the paging signal. In contrast, when the result of thecorrelation operation is equal to or smaller than the certain threshold,each of the mobile terminals determines that there is no paging destinedfor the mobile terminal itself, and makes a transition to reception ofMBMS-related information or makes a transition to a discontinuousreception operation if there is no necessity to receive any MBMS-relatedinformation. To which group each of the mobile terminals belongs can bedetermined by using a predetermined determining method, or can beinformed, as broadcast information, from either the serving cell using aunicast service or the MBMS dedicated cell to the mobile terminal itselfvia an upper layer.

In the above-mentioned example, the paging signal destined for each ofthe mobile terminals is allocated to a control information element unithaving a size corresponding to the size of the physical area onto whichthe paging signal is to be mapped. As an alternative, the paging signaldestined for each of the mobile terminals can be allocated to atransport block unit. In the case in which the paging signal destinedfor each of the mobile terminals is allocated to a transport block unit,the physical resource to which the paging signal is allocated can beincreased or decreased according to the amount of information, and theallocation to the physical area can be carried out with flexibility.

FIG. 34 shows another example of the method of mapping paging signalsonto the physical area on the PMCH onto which the paging signals are tobe mapped. Paging signals to mobile terminals n1, n2, and so on for eachof which an incoming call is occurring, among mobile terminals belongingto a paging group n, are mapped onto a physical area corresponding tothis group n. The base station performs CRC addition on the pagingsignal destined for each of the mobile terminals, and carries out aprocess including encoding and rate matching. The result of theseprocesses performed on the paging signal is multiplied by anidentification code (number) specific to the above-mentioned mobileterminal. This mobile-terminal-specific identification code is ascrambling code having orthogonality which is established among theresults of the processes by the scrambling codes of mobile terminals.The base station carries out multiplexing of the results of theprocesses by the scrambling codes, the number of the multiplexed resultsof the processes by the scrambling codes being equal to the number ofmobile terminals for each of which an incoming call is occurring. Thebase station then performs a scrambling process using anMBSFN-area-specific scrambling code, a modulation process, etc. on theresult of the multiplexing. The modulation process can be specific tothe MBSFN area. The result of carrying out these processes is mappedonto the physical area corresponding to the paging group n. In thiscase, the base station sets “1” to the paging signal presence or absenceindicator of the paging group n, and then maps it onto the physical areacorresponding to the paging group n of the paging signal presence orabsence indicator. The physical area corresponding to the paging group ncan be predetermined, or can be informed, as broadcast information, fromeither the unicast side serving cell or the MBMS dedicated cell to thebase station. Each of the mobile terminals receives the paging signalpresence or absence indicator of the paging group to which the mobileterminal itself belongs, and, when the paging signal presence or absenceindicator has a value of “1”, receives the physical area used for thepaging signal corresponding to this paging group. Each of the mobileterminals receives the physical area used for the paging signal, andcarries out demodulation and descrambling using the MBSFN-area-specificscrambling code. Each of the mobile terminals carries out blinddetection of the paging signal destined for the mobile terminal itselfby carrying out an operation of calculating a correlation withdescrambling and the mobile-terminal-specific identification number.When the result of the correlation operation is larger than a certainthreshold, each of the mobile terminals determines that there is pagingdestined for the mobile terminal itself, and starts an operation ofreceiving a paging incoming call with the decoded paging signal. Incontrast, when the result of the correlation operation is equal to orsmaller than the certain threshold, each of the mobile terminalsdetermines that there is no paging destined for the mobile terminalitself, and makes a transition to reception of MBMS-related informationor makes a transition to a discontinuous reception operation if there isno necessity to receive any MBMS-related information. To which groupeach of the mobile terminals belongs can be determined by using apredetermined determining method, or can be informed, as broadcastinformation, from either the serving cell using a unicast service or theMBMS dedicated cell to the mobile terminal itself via an upper layer.Instead of the paging signals described in FIGS. 33 and 34, a transportchannel onto which the paging signals are mapped can be provided. Thismethod can also be applied to the subsequent embodiments. What isnecessary is to use information onto which the paging signals arecarried, the information being paging-related information which eachmobile terminal requires when receiving a paging.

Some methods each of mapping paging signals onto an area on the PMCH onwhich the paging signals are to be mapped are disclosed, though themapping can be alternatively performed in such a way that theabove-mentioned area onto which the paging signals are to be mapped isan arbitrary predetermined area, a localized area (a physical areacontinuous on the frequency axis), or distributed areas (physical areasdistributed on the frequency axis).

In the above-mentioned example, the base station is configured in such away as to multiply the paging signal destined for each mobile terminalby a mobile-terminal-specific identification number or a scramblingcode. Because the base station is configured in this way, when theamount of information of the paging signal is the same at each of themobile terminals, it becomes able to equalize the sizes of the areas ofthe control information element units to be allocated by making theprocess including encoding (Encode) and rate matching be common amongthe mobile terminals. Therefore, because the sizes of the areas of thecontrol information element units on which each mobile terminal performsblind detection are limited to a single one, the number of times thatthe blind detection is carried out can be reduced and the time requiredfor each mobile terminal to perform the blind detection can also beshortened. Therefore, there is provided an advantage of accomplishingreduction in the circuit configuration of each mobile terminal,reduction in the power consumption of each mobile terminal, andreduction in the control delay time occurring in each mobile terminal.

By multiplying the paging signal destined for each of the mobileterminals by the mobile-terminal-specific identification number or thescrambling code, and then mapping it onto the area of the PMCH ontowhich the paging signal is mapped for each paging group, as mentionedabove, the necessity for each of the mobile terminals to receive all ofthe area used for paging signals can be eliminated, and each of themobile terminals has only to receive only a required area, i.e., aphysical area corresponding to the group to which the mobile terminalitself belongs. Therefore, the length of time required for each of themobile terminals to detect the paging signal destined therefor can beshortened. Furthermore, because each of the mobile terminals does nothave to receive the physical area corresponding to any other group towhich the mobile terminal itself does not belong, the power forreceiving of each of the mobile terminals can be reduced. In addition,by using the paging signal presence or absence indicator correspondingto each group, also when there are many mobile terminals, the pagingsignal presence or absence indicators can be provided by using a smallamount of physical resources. Furthermore, each of the mobile terminalshas only to receive an area used for the paging signal as needed.Therefore, while the power for receiving of each of the mobile terminalscan be reduced, the control delay time can also be reduced because eachof the mobile terminals can make a transition to the next operationimmediately when it does not have to receive the paging signal. As aresult, because each of the mobile terminals becomes able to carry outblind detection of whether or not it is information destined for themobile terminal itself by using the identification code specific to themobile terminal or the scrambling code, it becomes unnecessary to fixthe physical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, there is no necessityto provide a physical area used for the paging signals destined for allthe mobile terminals, and a physical area which is large enough to mappaging signals destined for a certain number of mobile terminals foreach of which an incoming call is predicted to actually occur has onlyto be provided. By using this method, it becomes able to use the limitedamount of physical resources effectively. Furthermore, by using theabove-mentioned method, the mobile communication system can flexiblydeal with even a case in which the number of mobile terminals for eachof which an incoming call is occurring becomes larger than a predictednumber through scheduling in the base station. For example, the mobilecommunication system can transmit a paging signal destined for a mobileterminal currently receiving a new incoming call on the PMCH onto whichthe next MCCH is mapped.

In the above-mentioned example, the base station multiplies the pagingsignal destined for each mobile terminal by a mobile-terminal-specificidentification number. As an alternative, the base station can use amethod of multiplying a CRC, instead of the paging signal, by amobile-terminal-specific identification number. The method ofmultiplying a CRC by a mobile-terminal-specific identification number iseffective for a case in which the amount of information of the pagingsignal destined for each of the mobile terminals differs.

Furthermore, in the above-mentioned example, by carrying out the processof multiplying the paging signal destined for each of the mobileterminals by the identification code specific to this mobile terminal,the base station enables each of the mobile terminals to carry out blinddetection of the paging information destined for the mobile terminalitself. The base station can alternatively use another processing methodof adding the paging signal destined for each of the mobile terminalsand the identification number specific to this mobile terminal. Forexample, in the process 1 shown in FIG. 33, the base station canalternatively use the other processing method of adding the pagingsignal destined for each of the mobile terminals and the identificationnumber specific to this mobile terminal, instead of multiplying thepaging signal by the identification number. In this case, each of themobile terminals receives the physical area used for the paging signal,carries out demodulation and descrambling using the MBSFN-area-specificscrambling code, and divides the result of the demodulation anddescrambling into parts each corresponding to an information elementunit, and performs a process including decoding on each of the dividedparts each corresponding to an information element unit. Each of themobile terminals then determines whether the mobile-terminal-specificidentification number exists in the information on which the mobileterminal itself has performed the process including decoding to detectthe paging signal destined therefor. By configuring the processing inthis way, the same advantages as those as mentioned above are provided.

In the above-mentioned example, the mapping method of mapping pagingsignals onto a physical area is disclosed. This method can be applied toalso a case of mapping an indicator showing whether or not a pagingsignal has been transmitted onto a physical area. Furthermore, in theabove-mentioned example, the base station multiplies the paging signaldestined for each mobile terminal by the identification number specificto the mobile terminal. The base station can multiply the indicatorshowing whether or not the paging signal has been transmitted by themobile-terminal-specific identification code (UE-ID or RNTI), or can addthe mobile-terminal-specific identification code to the indicator.Furthermore, the base station is configured in such a way as to add aCRC to the indicator showing whether or not the paging signal has beentransmitted, and can also use a method of multiplying the CRC by themobile-terminal-specific identification number. As a result, becauseeach of the mobile terminals becomes able to carry out blind detectionof whether or not it is information destined for the mobile terminalitself by using the identification code specific to the mobile terminal,it becomes unnecessary to fix the physical area onto which the indicatorshowing whether or not the paging signal destined for each of the mobileterminals has been transmitted is mapped in advance. Furthermore, thephysical area onto which this indicator can be mapped can bepredetermined, or can be broadcast. By thus predetermining orbroadcasting the physical area, the physical resources can be used withflexibility. As will be mentioned below, these methods are effective fornot a case in which the indicator showing whether the paging signal hasbeen transmitted is 1-bit information, but a case in which the amount ofinformation transmitted to each of the mobile terminals, such asinformation about allocation of a paging message, differs.

When mapping the paging signal onto the PMCH, it is necessary todistinguish the paging signal from other information, e.g., an MCCH andan MTCH. In the above-mentioned method, by disposing the physical areaused for the paging signal, or multiplying the paging signal by themobile-terminal-specific identification number or adding thisidentification number to the paging signal, the paging signal isdistinguished from other information. In accordance with another method,each information which is to be mapped onto the PMCH can be multipliedby an identifier (ID) specific to the type of the information. As analternative, only a specific type of information can be multiplied by anidentifier specific to the specific type of information. Because anidentifier specific to a specific type of information is used for MBSFNsubframes which are transmitted via a multi-cell transmission scheme,unlike in the case of unicast communications, an identical identifierspecific to a specific type of information needs to be transmitted froma plurality of cells which carry out multi-cell transmission. Forexample, an identifier specific to each identical information type isused in each MBSFN area. As a concrete example, a case in which a pagingsignal, an MCCH, and an MTCH are transmitted via the PMCH from the MBMSdedicated cell is considered. The MBMS dedicated cell multiplies thepaging signal by an identifier used for the paging signal, multipliesthe MCCH by an identifier for the MCCH, multiplies the MCCH by anidentifier for the MCCH, and transmits them by using the PMCH. A mobileterminal which needs to receive the paging signal, among mobileterminals being served by the MBMS dedicated cell, carries out blinddetection of the paging signal by using the identifier for the pagingsignal. A mobile terminal which needs to receive the MTCH or MCCH, amongthe mobile terminals being served by the MBMS dedicated cell, carriesout blind detection of the MTCH or MCCH by using the identifier for theMTCH or MCCH. As a result, there can be provided an advantage ofenabling such a mobile terminal to receive required information when themobile terminal requires the information. Accordingly, there can beprovided an advantage of reducing the power consumption of the mobileterminal. There can be provided a further advantage of preventing acontrol delay time from occurring in the mobile terminal. The identifierdifferent for each information type can be predetermined, or can bebroadcast via broadcast information from the serving cell. As analternative, the identifier different for each information type can bebroadcast from the MBMS dedicated cell. Furthermore, because each of themobile terminals becomes able to carry out blind detection when thepaging signal is multiplied by or added to the mobile-terminal-specificidentifier, it becomes unnecessary to fix the physical area onto whichthe paging signal destined for each of the mobile terminals is mapped inadvance. Therefore, the mapping can be carried out with flexibility, andthere is provided an advantage of improving the use efficiency of thephysical resources.

By using the method of carrying paging signals on the PMCH which isdisclosed above in this Embodiment 7, the mobile communication systemcan transmit the paging signals destined for all the mobile terminalseach of which is receiving or trying to receive an MBMS service from theMBMS dedicated cell to make it possible for each of the above-mentionedmobile terminals to receive the paging signal from the MBMS dedicatedcell.

Hereafter, a variant of this Embodiment 7 will be explained. InEmbodiment 7, the method of, in order to enable each mobile terminal toreceive the paging signal from the MBMS dedicated cell, carrying thepaging signal on the PMCH of each MBSFN area is disclosed. The methodof, when configuring the PMCH, carrying out either time divisionmultiplexing (TDM) or code division multiplexing (CDM) for the PMCH ofeach MBSFN area is disclosed above. In the first variant which will beexplained hereafter, a method of, when configuring the PMCH, carryingout both time division multiplexing (TDM) and code division multiplexing(CDM) for each MBSFN area.

FIG. 41 is an explanatory drawing showing the configuration of the PMCHdisposed for each MBSFN area. In FIG. 41, both time divisionmultiplexing (TDM) and code division multiplexing (CDM) are used foreach MBSFN area. A cell #n1 is one located in an MBSFN area 1, a cell#n2 is one located in an MBSFN area 2, and a cell #n3 is one located inan MBSFN area 3. Furthermore, the cells #1, #2, and #3 also belong to anMBSFN area 4. Code division multiplexing of the PMCHs of the MBSFN areas1, 2, and 3 is carried out, and time division multiplexing of the PMCHsof the MBSFN areas 1, 2, and 3 and the PMCH of the MBSFN area 4 iscarried out. Because the cell #n1 belongs to the MBSFN area 1, the PMCHcorresponding to the MBSFN area 1 is transmitted at a time. The PMCH istransmitted on an MBSFN subframe because the PMCH is transmitted via amulti-cell transmission scheme in each MBSFN area. A set of MBSFN framesto which MBSFN subframes are allocated is referred to as an “MBSFN framecluster” (MBSFN frame cluster). In the MBMS dedicated cell, allsubframes in an MBSFN frame can be MBSFN subframes used for multi-celltransmission. The length of each of the repetition periods at which theMBSFN frame cluster corresponding to a certain MBSFN area is repeated isexpressed as the “MBSFN frame cluster repetition period” (MBSFN framecluster repetition period). An MCH which is a transport channel for MBMSis mapped onto the PMCH, and either or both of a logical channel MCCHwhich is control information for MBMS and a logical channel MTCH whichis data for MBMS are mapped onto the MCH.

The MCCH and the MTCH can be divided in time and mapped onto the PMCH,or can be divided in time and mapped onto a physical area which istransmitted via a multi-cell transmission scheme. For example, the MCCHand the MTCH can be mapped onto different MBSFN subframes which are thephysical area onto which they are finally mapped. The MCCH can be mappedonto each MBSFN frame cluster, or only the MTCH can be mapped onto eachMBSFN frame cluster. In a case in which only the MTCH is mapped onto thePMCH, the repetition period of the MCCH differs from the repetitionperiod of the MBSFN frame cluster. Furthermore, there is a case in whicha plurality of MCCHs are mapped onto an MBSFN frame cluster. The lengthof each of the repetition periods at which the MCCH is repeated isexpressed as the “MCCH repetition period” (MCCH Repetition period). InFIG. 41, MCCH1 is MBMS control information for the MBSFN area 1, andMTCH1 is MBMS data for the MBSFN area 1. Similarly, MCCH2 is MBMScontrol information for the MBSFN area 2, MTCH2 are MBMS data for theMBSFN area 2, MCCH3 is MBMS control information for the MBSFN area 3,and MTCH3 is MBMS data for the MBSFN area 3. Code division multiplexingof the PMCH of the cell #n1, the PMCH of the cell #n2, and the PMCH ofthe cell #n3 is carried out, and they are transmitted at the same time.Because the cell #n1 (or the cell #n2 or #n3) belongs to the MBSFN area1 (or 2 or 3) and the MBSFN area 4, time division multiplexing of thePMCH of the MBSFN area 1 (or 2 or 3) and the PMCH of the MBSFN area 4 iscarried out. Because multi-cell transmission of the PMCH of the MBSFNarea 4 is carried out in the MBSFN area 4, the transmission of the PMCHin each of the cells #n1, #n2, and #n3 is carried out at the same time.By thus using the method of carrying out both time division multiplexingand code division multiplexing for the PMCH of each MBSFN area, forexample, time division multiplexing can be used for MBSFN areas whichoverlap one another and code division multiplexing can be used for MBSFNareas which do not overlap one another. Therefore, as compared with thecase of using only time division multiplexing, the efficiency of theradio resources can be improved because code division multiplexing isused. Furthermore, as compared with the case of using only code divisionmultiplexing, the mutual interference among MBSFN areas which overlapone another can be reduced and receive errors detected in MBMS datareceived by each mobile terminal can be reduced.

Next, the configuration of each PMCH which enables each mobile terminalto receive paging from the MBMS dedicated cell will be described. Bothtime division multiplexing and code division multiplexing are used foreach MBSFN area. Therefore, two or more PMCHs transmitted from each cellalso exist for each MBSFN area. In order to deal with a case in whichtwo or more PMCHs for each MBSFN area exist in one cell, paging signalsare configured in such a way as to be mapped onto the PMCHscorresponding to all the MBSFN areas. The method of including pagingsignals as shown in FIG. 32 can be applied to the PMCH of each MBSFNarea. In accordance with this configuration, a mobile terminal which isbeing located in an area in which it can receive MBMS services providedby a plurality of MBSFN areas receives the MCCH of either one of theMBSFN areas from which the mobile terminal is receiving or trying toreceive an MBMS service, so that the mobile terminal can receive pagingwhen receiving the above-mentioned MCCH. Because the mobile terminaldoes not have to receive the MCCH of an MBSFN area providing an MBMSservice different from the MBMS service which the mobile terminal isreceiving, and can therefore carry out discontinuous reception, themobile terminal can reduce its power consumption. As another method, aconfiguration of carrying a paging signal on the PMCH of one MBSFN areawill be described. For example, the configuration is formed in such away that an MCCH (P-MCCH) is mapped onto only the PMCH of the smallestone of MBSFN areas to which one cell belongs and no MCCH is mapped ontothe PMCH of any other MBSFN area, and the method of carrying a pagingsignal as shown in FIG. 32 is applied to the PMCH of the smallest MBSFNarea. MBMS control information about another MBSFN area is included inthe MCCH (P-MCCH) mapped onto the PMCH of the smallest MBSFN area.

Because the configuration is formed in this way, even when, for example,the mobile terminal is receiving an MBMS service from either of theplurality of MBSFN areas, the mobile terminal becomes able to receivepaging by receiving the MCCH (P-MCCH) of the smallest MBSFN area whenreceiving this MCCH (P-MCCH). In addition, the mobile terminal does nothave to change the paging repetition period according to a change in theMBMS service to receive, in this case, the MCCH repetition period (MCCHrepetition period), and can therefore simplify its control operation. Inaddition, because it becomes able to map only the MTCH onto the PMCH ofanother MBSFN area, there is provided an advantage of being able toimprove the efficiency of the radio resources in the system.Furthermore, in accordance with an another method, the MCCHcorresponding to another MBSFN area can also be mapped onto the PMCH ofthe smallest MBSFN area. Also in this case, the method of carrying apaging signal as shown in FIG. 32 can be applied to this PMCH. As aresult, the same advantage is provided while each MCCH can betime-divided and mapped onto a physical area. Therefore, the mobileterminal can receive the MCCH of a desired MBSFN area, and carry outdiscontinuous reception of a physical area via which another MCCH istransmitted. A configuration of carrying a paging signal on the PMCH ofone MBSFN area will be described as another method. For example, theconfiguration is formed in such a way that a primary MCCH (P-MCCH) ismapped onto the PMCH of an MBSFN area to which one cell belongs and asecondary MCCH (S-MCCH) is mapped onto the PMCH of another MBSFN area,and the method of carrying a paging signal as shown in FIG. 32 isapplied to a PMCH onto which a PCCH is mapped. Because the configurationis formed in this way, even when, for example, the mobile terminal isreceiving an MBMS service from either of the plurality of MBSFN areas,the mobile terminal becomes able to receive paging by receiving theP-MCCH when receiving this P-MCCH. In addition, the mobile terminal doesnot have to change the paging repetition period according to a change inthe MBMS service to receive, in this case, the MCCH repetition period(MCCH repetition period), and can therefore simplify its controloperation. As the method of mapping a paging signal onto a physical areaon a PMCH onto which the paging signal is mapped, the method disclosedin FIG. 33 or 34 can be applied.

In above-mentioned Embodiment 7 and the variant, the case in which aplurality of cells exist in an MBSFN area is shown. The presentinvention can also be applied to a case in which the number of cells inan MBSFN area is only one. In this single cell, the PMCH configurationas disclosed in FIG. 32 and the method, as disclosed in FIG. 33, ofmapping a paging signal onto a physical area on the PMCH onto which thepaging signal is mapped can be applied. In the case in which only onecell exists in an MBSFN area, no SFN gain caused by typical multi-celltransmission is acquired even though transmission using the PMCH iscarried out, though an MBMS service can be limited to a certain narrowarea and it becomes able to provide a so-called spot service. Inaddition, there can be a case in which only one cell exists in an MBSFNarea, and in this single cell, MBMS service data corresponding to thisMBSFN area are not transmitted while only MBMS control information istransmitted. In this case, no MTCH is mapped onto the PMCH, but only theMCCH is mapped onto the PMCH. MBMS control information (MCCH) aboutanother MBSFN area to which the single cell belongs can be included inthe above-mentioned MCCH. Accordingly, because it becomes unnecessary tomap each MCCH onto the PMCH of any other MBSFN area, the efficiency ofthe radio resources can be improved. In addition, because the mobileterminal receives only the MCCH corresponding to this MBSFN area, themobile terminal becomes able to receive all MCCHs of one or morereceivable MBSFN areas without receiving any other PMCH. Therefore, themobile terminal can reduce the control delay time at the time of MBMSservice reception. Furthermore, when the mobile terminal does not haveto receive the MBMS service information about any other MBSFN area, themobile terminal can carry out a discontinuous reception operation,thereby being able to reduce the power for receiving.

In this embodiment, the configuration of disposing the indicator showingwhether or not the paging signal has been transmitted is disclosed. Asan alternative, information about the allocation of the paging signalcan be provided as this indicator. As a result, when a mobile terminalreceives the information about the allocation of the paging signal tothe mobile terminal itself, the mobile terminal can judge that paging isoccurring. As an example of the information about the allocation of thepaging signal, information showing a physical area onto which a pagingsignal transmitted via the same subframe, e.g., a paging message ismapped can be provided. By thus defining the information about thephysical area as the allocation information, the mobile terminal whichhas received the information about the allocation of the paging messagehas only to receive only this physical area in order to receive thepaging message, and therefore does not have to receive any otherphysical area. Therefore, the mobile terminal's power consumption at thetime of receiving the paging message can be reduced. Furthermore, itbecomes unnecessary to transmit beforehand the information about thephysical area to which the paging signal is allocated to the mobileterminal via broadcast information or the like, and the amount ofsignaling can be reduced. Furthermore, because it becomes able tocarryout the allocation of the paging signal to the physical area withflexibility, there is provided an advantage of improving the useefficiency of the radio resources.

Embodiment 8

In Embodiment 7, the method of, in order to enable a mobile terminal toreceive paging from an MBMS dedicated cell in which any unicast serviceis not supported, carrying a paging signal onto a physical multicastchannel (PMCH) of each MBSFN (Multimedia Broadcast multicast serviceSingle Frequency Network) area is disclosed. In this Embodiment 8, amethod of disposing a physical channel dedicated to paging which istransmitted via a multi-cell transmission scheme in an MBSFN area, andcarrying a paging signal onto this physical channel will be disclosed.

FIG. 42 is an explanatory drawing showing the structure of a physicalchannel dedicated to paging which is transmitted via a multi-celltransmission scheme in an MBSFN area. A certain cell is configured insuch a way that a part of MBSFN subframes corresponding to the MBSFNarea to which this cell belongs is defined as a physical channeldedicated to paging (Dedicated Physical Channel: DPCH), and the DPCH isdisposed in each subframe. As shown in Embodiment 7, because any unicastservice is not supported in an MBMS dedicated channel, all the subframesof an MBSFN frame can be MBSFN subframes. As an example, a method ofmapping a paging signal onto the physical channel dedicated to paging isshown in FIG. 56. FIG. 56 is an explanatory drawing showing a mappingmethod in a case of carrying a logical channel PCCH including a pagingsignal onto a transport channel PCH, carrying out multiplexing oflogical channels MTCH and MCCH to carry them onto a transport channelMCH, and further carrying the PCH onto the physical channel dedicated topaging. The logical channel PCCH onto which the paging signal is mappedis mapped onto the transport channel PCH, and this PCH is further mappedonto the DPCH which is the physical channel dedicated to paging. On theother hand, as usual, MBMS-related information is mapped onto thelogical channels MTCH and MCCH, and they are mapped onto the transportchannel MCH and this MCH is further mapped onto the physical channelPMCH. The DPCH is configured in such a way as to be transmitted via amulti-cell transmission scheme in the MBSFN area, and the DPCH and thePMCH are multiplexed into an identical MBSFN subframe and aretransmitted.

In a case in which the PMCHs of MBSFN areas are configured in such a wayas to be code division multiplexed, as shown in, for example, FIG. 40,the PMCHs are transmitted via continuous MBSFN subframes. In this case,the DPCH can be disposed in all the subframes on the time axis.Therefore, as compared with Embodiment 7, the number of times that thepaging signal can be transmitted increases. By thus defining a part ofeach of MBSFN subframes which are transmitted via a multi-celltransmission scheme in an MBSFN area as a DPCH used for transmission ofpaging signal, the frequency of the transmission of a paging signal isincreased in the system, and the number of mobile terminals each ofwhich can receive paging from an MBMS dedicated cell can be increased.Furthermore, because a shortage of the area for paging can be avoided atthe time of occurrence of paging to a mobile terminal which can receivethe paging, it becomes able to shorten the delay time occurring in thetransmission of the paging information. In the above-mentioned example,the case in which the PMCHs of MBSFN areas are configured in such a wayas to be code division multiplexed (CDM) is described. In contrast, evenin a case in which the PMCHs of MBSFN areas are configured in such a wayas to be time division multiplexed (TDM), or even in a case in whichboth time division multiplexing and code division multiplexing areapplied to the PMCHs of MBSFN areas, a DPCH can be disposed in all MBSFNsubframes via which a PMCH corresponding to one or more MBSFN areas towhich a cell belongs is transmitted. As a result, because the number oftimes that the paging signal can be transmitted can be increased ascompared with Embodiment 7, the same advantage can be provided.

FIG. 43 is an explanatory drawing showing the configuration of an MBSFNsubframe. In FIG. 43, a DPCH and a PMCH are time division multiplexedwithin an MBSFN subframe. A paging signal is mapped onto the DPCH andMBMS-related information is mapped onto the PMCH. By separatelyproviding the physical channels onto which the paging signal and theMBMS-related information are mapped, abase station can perform encodingoperations on the paging signal and the MBMS-related informationrespectively and a mobile terminal can perform decoding operations onthe paging signal and the MBMS-related information respectively whenreceiving them. Furthermore, because the physical areas can be timedivision multiplexed, the mobile terminal does not have to receive thePMCH when it is not receiving any MBMS service, but is receiving onlythe paging information, and can therefore carry out discontinuousreception (Discontinuous Reception) while the PMCH is transmittedthereto, thereby being able to reduce its power consumption. Incontrast, when the mobile terminal does not have to receive the paginginformation, the mobile terminal does not have to receive the DPC andcan therefore carry out a discontinuous reception operation while theDPCH is transmitted thereto. Therefore, the mobile terminal can reduceits power consumption. The DPCH is transmitted within k OFDM symbols ofeach MBSFN subframe. The value of k can be determined beforehand, or canbe informed via broadcast information of an MBMS dedicated cell. Thevalue of k can be alternatively informed via broadcast information of aunicast cell.

As an alternative, a PCFICH (Physical control format indicator channel)can be disposed for each subframe as a channel showing the number k ofOFDM symbols via which the DPCH is transmitted. The PCFICH istransmitted via the first OFDM symbol of each subframe. Informationabout the allocation of the physical resource to the PCFICH can benotified to the mobile terminal via broadcast information from the MBMSdedicated cell, or can be notified via broadcast information from theunicast cell while being related to information about the frequencylayer of the MBMS dedicated cell. As an alternative, the informationabout the allocation of the physical resource to the PCFICH can bepredetermined. In the case in which the information about the allocationof the physical resource to the PCFICH is predetermined, the amount ofinformation which is required for the notification can be reduced. Bythus indicating the value of k for each subframe, it becomes able tochange the value of k for each subframe, and it therefore becomes ableto dynamically change the transmission area in which the MBMSinformation is transmitted and the transmission area in which the DPCHis transmitted. The value of k can range from 0 to a maximum number ofOFDM symbols in each subframe. For example, k can be set to be equal tothe number of OFDM symbols as that included in a PDCCH (Physicaldownlink control channel) of the unicast cell, i.e., 1, 2, or 3. In thiscase, the PCFICH is 2 bits in size. For example, k can be set to beequal to the number of OFDM symbols as that included in a PDCCH in anMBSFN subframe of the MBMS/unicast-mixed cell, i.e., 1 or 2. In thiscase, the PCFICH is 2 bits or 1 bit in size. The PCFICH of the unicastcell is multiplied by a cell specific scrambling code. In contrast tothis, in accordance with the present invention, in order to also enablethe PCFICH to be transmitted via a multi-cell transmission scheme in theMBSFN area, the PCFICH is configured in such a way as to be multipliedby an MBSFN-area-specific scrambling code. By configuring the PCFICH inthe above-mentioned way, the mobile terminal becomes able to carry outdecoding (Decode) by using the same method as that which the mobileterminal uses when decoding information from the unicast cell, and cantherefore simplify the receiving circuit thereof.

The unicast cell uses a PDSCH or PDCCH in order to transmit a pagingsignal, while it is necessary to include resource allocation (ResourceAllocation) information in the paging signal. This is because theunicast cell needs resource allocation to carry out communications afterthe paging. A resource for the communications after the paging istransmitted by using the PDSCH. This PDSCH is transmitted via theremaining OFDM symbol areas excluding the OFDM symbol areas via whichthe PDCCH in each subframe is transmitted. In the paging method inaccordance with the present invention, because the communications afterthe paging is carried out by the unicast cell, only a paging indicator(Paging Indicator: PI) informing the presence or absence of an incomingcall can be transmitted as the paging information to be transmitted byusing the DPCH. This is because it is not necessary to transmit theresource allocation information for the communications after the paging.In order to make it possible to specify a mobile terminal by using onlya paging indicator, what is necessary is just to enable uniquedetermination of an MBSFN frame or an MBSFN subframe in which a pagingindicator to a certain mobile terminal exists from an identificationnumber (ID) specific to this mobile terminal. In accordance with anothermethod, the base station is enabled to multiply the paging indicator bythe mobile-terminal-specific identification number, and the mobileterminal is enabled to carry out blind detection by using thismobile-terminal-specific identification number. As an alternative, thetwo above-mentioned methods can be combined. For example, each mobileterminal is classified into a group according to an identificationnumber (ID) specific to this mobile terminal, an MBSFN frame or an MBSFNsubframe in which a paging indicator to this group exists is uniquelybrought into correspondence with the group, and the paging indicator ismultiplied by the mobile-terminal-specific identification number by thebase station.

Each mobile terminal can receive an MBSFN frame or an MBSFN subframeonto which the paging indicator to the group to which the mobileterminal belongs is mapped, the group being determined from theidentification number specific to this mobile terminal, and can carryout blind detection by using the identification number specific to themobile terminal itself. A method of determining the MBSFN frame or theMBSFN subframe in which the paging indicator to the mobile terminal orthe group to which the mobile terminal belongs exists from theidentification number specific to the mobile terminal can bepredetermined, or can be informed, as broadcast information, from eitherthe MBMS dedicated cell or the unicast cell to the mobile terminal viaan upper layer. The MBSFN frame or the MBSFN subframe in which thepaging indicator exists can be made to exist periodically. Because it isnot necessary to transmit the resource allocation information, itbecomes able to configure the DPCH from a smaller amount of information,and it therefore becomes able to transmit the MBMS-related informationwith the remaining area in the same subframe. Instead of mapping thepaging indicator onto the PCCH as shown in FIG. 56, the paging indicatorcan be mapped directly onto the DPCH in the physical layer. It alsobecomes able to transmit the DPCH with all the OFDM symbols in eachsubframe. For example, in a case in which the number of OFDM symbols ineach subframe is 7 at the maximum, an arbitrary number k ranging from 0to 7 of OFDM symbols can be used for the transmission of the DPCH bymaking the PCFICH be 3-bit information showing the value of k. It thusbecomes able to change and combine the transmission area in which theMBMS information is transmitted and the transmission area in which theDPCH is transmitted for each subframe with flexibility, and thereforethe efficiency of the radio resources can be improved.

In the present invention, the case of using an MBMS dedicated cell isdescribed. In the case of using an MBMS/unicast-mixed cell, both aunicast service and an MBMS service can be provided, and thereforepaging in the case of using an MBMS/unicast-mixed cell needs resourceallocation for communications after the paging. However, because an MBMSservice can be carried out in an MBMS/unicast-mixed cell, there existMBSFN subframes for carrying out MC transmission of broadcast type MBMSdata. Because there is no PDSCH in an MBSFN subframe, when the pagingmethod for use in a unicast cell is applied to an MBMS/unicast-mixedcell, there arises a problem that no area onto which the resourceallocation information destined for each mobile terminal is mapped canbe ensured in each MBSFN subframe. In this case, by using a method oflimiting the subframes via which the paging indicator is to betransmitted to subframes in which a PDSCH resides in advance, or amethod of transmitting the allocation information by using the PDCCH ofa subframe in which a PDSCH exists for the first time after a pagingsignal has been transmitted, the paging can be carried out in anMBMS/unicast-mixed cell.

In a concrete example of the above-mentioned method of, in anMBMS/unicast-mixed cell, limiting the subframes via which the pagingindicator is to be transmitted to the ones in each of which a PDSCHexists in advance, subframes in which a PDSCH onto which the pagingsignal is mapped exists are defined as the ones via which the pagingindicator is to be transmitted. As a result, because it becomes able toadjust the number of subframes onto which the paging signal is mapped inthe PDSCH according to the number of mobile terminals being served bythe cell, the utilization efficiency of the radio resources is improved.It becomes unnecessary for each mobile terminal to receive all thesubframes in each of which the PDSCH exists, each mobile terminal canachieve low power consumption.

In the case of paging using an MBMS/unicast-mixed cell, when theresource allocation information does not have to be mapped onto a PDSCHfor communications after the paging, the method of making it possible tospecify a mobile terminal by using only a paging indicator as mentionedabove can be applied. In this case, what is necessary is just to carrythe paging indicator onto an area of a PDCCH. In an MBSFN subframe, whatis necessary is just to carry the paging indicator on an area which isallocated for unicast, i.e., one or two leading OFDM symbol areas. As aconcrete method, the above-mentioned method of using a paging dedicatedchannel (DPCH) can be applied. The above-mentioned method of using aPCFICH can be applied also to the number of symbols to be used, and kcan be set to 0 or 1. Each mobile terminal has only to receive a radioframe or a subframe onto which the paging indicator of the group towhich the mobile terminal belongs is mapped, the group being determinedfrom the identification number specific to this mobile terminal, and tocarry out blind detection by using the identification number specific tothe mobile terminal itself. In a case in which, in the paging using anMBMS/unicast-mixed cell, the resource allocation information does nothave to be mapped onto a PDSCH for communications after the paging,there can be provided, for example, a method of enabling each mobileterminal to transmit an uplink RACH to a base station in order to make arequest of the base station for resource allocation after the mobileterminal has received the paging indicator. When the method configuredin this way is provided, the base station does not have to carry theresource allocation information on the PDSCH in the same subframes ontowhich the paging indicator is mapped. Because the method is configuredin this way, also in the case of the paging using an MBMS/Unicast-mixedcell, the paging signal (the paging indicator) can be transmitted witharbitrary radio frames or subframes regardless of whether or not thereexists an MBSFN subframe.

FIG. 44 is an explanatory drawing showing a method of mapping a pagingsignal onto a paging dedicated channel (DPCH). FIG. 44 shows only apaging indicator (Paging Indicator: PI) as the paging signal. The pagingindicator is paging information which is expressed as a 1-bit numberhaving a value of 1 or 0, and shows the presence or absence of anincoming call. The base station sets “1” to the paging indicator for amobile terminal for which an incoming call is occurring, and maps thepaging indicator onto the paging dedicated physical channel. The basestation multiplies the paging indicator destined for each mobileterminal m for which an incoming call is occurring by an identificationnumber specific to this mobile terminal (process 1). Next, the basestation performs CRC (Cyclic Redundancy Check) addition on the result ofthis multiplication (process 2), and carries out a process includingencoding (Encode), rate matching, and interleaving (process 3). The basestation then allocates the result of the series of processes which ithas carried out to a control information element having a sizecorresponding to the size of the physical area onto which the pagingindicator is to be mapped, and connects a plurality of controlinformation elements whose number is equal to that of the mobileterminals for each of which an incoming call is occurring to one another(process 4). The base station performs a scrambling process using anMBSFN-area-specific scrambling code (Scrambling Code), a modulationprocess, etc. on the connected result (process 5). The modulationprocess can be specific to the MBSFN area. The result of carrying outthese processes is mapped onto k leading OFDM symbols (process 6). Atthat time, the base station derives the number k of required OFDMsymbols on the basis of the result of the connection of the plurality ofcontrol information elements whose number is equal to that of the mobileterminals for each of which an incoming call is occurring, and performsa process including encoding on the indicator corresponding to thenumber k and then maps the indicator onto the PCFICH. These processesare carried out by using the same method in all the cells in the MBSFNarea, and multi-cell transmission of the paging indicator is carried outin the MBSFN area. In this embodiment, a case in which the number (k) ofOFDM symbols via which the DPCH is transmitted is set to 1 will beshown. The DPCH is mapped onto the first OFDM symbol of each subframetogether with the PCFICH and a reference symbol. In FIG. 44, A shows oneOFDN symbol, and B shows the PCFICH and the reference symbol.

A mobile terminal which has received a signal which is transmittedthereto via a multi-cell transmission scheme determines the number ofOFDM symbols used for the paging on the basis of the result of decodingthe received PCFICH, and then carries out a demodulation process, adescrambling (Descrambling) process, and so on. After performing thoseprocesses, the mobile terminal divides the result of the processes intoparts each corresponding to a certain area, and successively performsdeinterleaving, decoding (Decoding), error detection, a correctionprocess, etc. on each of the parts to carry out blind detection of theterminal-specific identification number. After the mobile terminaldetects the identification number specific to the mobile terminal itselfthrough the blind detection, the mobile terminal can determine thatpaging is occurring. The PCFICH, the reference symbol, and so on aremapped onto a physical resource by using, for example, a predeterminedmethod. As an alternative, the same method as that used by the unicastcell can be used. By using the same method as that used by the unicastcell, it becomes able to simplify the configuration of the base stationand the configuration of the receiving circuit of each mobile terminal.In the case in which each mobile terminal receives the same amount ofinformation, like in the case in which the paging signal is only thepaging indicator, the control information element units to each of whichthe result of the encoding is allocated can be set to have only onesize. By making all mobile terminals which receive paging carry outidentical processing including an identical encoding process, thecontrol information element units which are obtained after the encodingcan be set to have only one size. As a result, when carrying out blinddetection of the mobile-terminal-specific identification number, eachmobile terminal has only to a process including decoding on each of thecontrol information element units having an only one size. Therefore,each mobile terminal can reduce the length of time required to carry outthe blind detection and can therefore improve its detection speed.Instead of multiplying the paging indicator by themobile-terminal-specific identification number, a code specific to eachmobile terminal can be provided as the paging indicator. In this case,the same advantage can be provided.

In the above-mentioned example, the paging signal destined for each ofthe mobile terminals is allocated to a control information element unithaving a size corresponding to the size of the physical area onto whichthe paging signal is to be mapped. As an alternative, the paging signaldestined for each of the mobile terminals can be allocated to atransport block unit. In the case in which the paging signal destinedfor each of the mobile terminals is allocated to a transport block unit,the physical resource to which the paging signal is allocated can beincreased or decreased according to the amount of information, and theallocation to the physical area can be carried out with flexibility.

Furthermore, in the above-mentioned example, the base station carriesout the process 1 of multiplying the paging signal destined for each ofthe mobile terminals by an identification code specific to this mobileterminal. The base station can alternatively use another processingmethod of adding the paging signal destined for each of the mobileterminals and an identification number specific to this mobile terminal.In this case, each of the mobile terminals receives the physical areafor paging signal, carries out demodulation and descrambling using anMBSFN-area-specific scrambling code, and divides the result of thedemodulation and descrambling into parts each corresponding to aninformation element unit, and performs a process including decoding oneach of the divided parts each corresponding to an information elementunit. Each of the mobile terminals then determines whether theidentification number specific to the mobile terminal itself exists inthe information on which the mobile terminal itself has performed theprocess including decoding to detect the paging signal destinedtherefor.

FIG. 45 is an explanatory drawing showing a method of mapping a pagingsignal onto a paging dedicated channel (DPCH). FIG. 45 shows a pagingindicator (PI) as the paging signal. In FIG. 45, the same referencenumerals as those in FIG. 44 denote the same processes or likeprocesses. The paging indicator is paging information which is expressedas a 1-bit number having a value of 1 or 0, and shows the presence orabsence of an incoming call. A base station sets “1” to the pagingindicator to each of mobile terminals for which an incoming call isoccurring, and maps the paging indicator onto the paging dedicatedphysical channel. The base station performs CRC addition on the pagingsignal destined for each of the mobile terminals (process 2), andcarries out a process including encoding (Encode), rate matching, andinterleaving (process 3). The base station multiplies the result ofcarrying out these processes by an identification code (number) specificto this mobile terminal (process 1′). This mobile-terminal-specificidentification code is a scrambling code having orthogonality which isestablished among the results of the processed by the scrambling codesof mobile terminals. The base station carries out multiplexing of theresults of the processes by the scrambling codes, the number of themultiplexed results of the processes by the scrambling codes being equalto the number of mobile terminals for each of which an incoming call isoccurring (process 7). The base station then performs a scramblingprocess using an MBSFN-area-specific scrambling code (Scrambling Code),a modulation process, etc. on the result of the multiplexing (process5). The modulation process can be specific to the MBSFN area. The resultof carrying out these processes is mapped onto k leading OFDM symbols(process 6). When the number of mobile terminals is large, the basestation divides them into a plurality of groups and carries outmultiplexing of the results of the processes by scrambling codesspecific to mobile terminals included in each group, the number of themultiplexed results of the processes by the scrambling codes being equalto the number of the mobile terminals, in such a way that orthogonalityis established among the mobile terminals included in each group, andthen carries out a spreading process using an MBSFN-area-specificscrambling code, a modulation process, etc. After carrying out theseprocesses for each group, the base station can map them onto differentOFDM symbols. At that time, the base station derives the number k ofrequired OFDM symbols on the basis of the result of the multiplexing ofthe results of the processes by the scrambling codes, the number of themultiplexed results of the processes by the scrambling codes being equalto that of the mobile terminals for each of which an incoming call isoccurring, and performs a process including encoding on the indicatorcorresponding to k and then maps the indicator onto the PCFICH. Theseprocesses are carried out by using the same method in all the cells inthe MBSFN area, and multi-cell transmission of the paging indicator iscarried out in the MBSFN area. In this embodiment, a case in which thenumber (k) of OFDM symbols via which the DPCH is transmitted is set to 1will be shown. The DPCH is mapped onto the first OFDM symbol of eachsubframe together with the PCFICH and a reference symbol. A mobileterminal which has received a signal which is transmitted thereto via amulti-cell transmission scheme determines the number of OFDM symbolsused for the paging from the received physical resource on the basis ofthe result of decoding the received PCFICH, and then carries out ademodulation process, a descrambling process, and so on. Afterperforming those processes, the mobile terminal divides the result ofthe processes into parts each corresponding to a certain area, andcarries out an operation of calculating a correlation with theterminal-specific identification number to carry out blind detection ofthe terminal-specific identification number. After the mobile terminalhas detected the identification code of the mobile terminal through theblind detection, the mobile terminal can determine that paging isoccurring. The mobile terminal then carries out deinterleaving,decoding, error detection, a correction process, etc. to receive thepaging signal.

Some methods each of mapping paging signals onto the paging dedicatedchannel (DPCH) are disclosed, though the mapping can be alternativelyperformed in such a way that the above-mentioned paging dedicated areaonto which the paging signals are to be mapped is an arbitrarypredetermined area, a localized area (a physical area continuous on thefrequency axis), or distributed areas (physical areas distributed on thefrequency axis).

The physical area onto which the paging signals are mapped can be aphysical area specific to each MBSFN area. The physical area specific toeach MBSFN area can be predetermined, or can be derived from theMBSFN-area-specific number (MBSFN area ID) or the like. In this case,the physical area can be derived by using a common computationexpression in the network side, the base station side, and each mobileterminal. Furthermore, a part of the paging signals can be mapped ontothe physical area specific to each MBSFN area, and the remainder can bemapped onto a physical area which is not specific to each MBSFN area. Ina concrete example, the information showing the presence or absence ofan incoming call which is included in the paging signal (e.g., 1-bitinformation showing the presence or absence of an incoming call, orinformation about allocation of a paging message) is mapped onto thephysical area specific to each MBSFN area, and other paging information(e.g., a paging message) is mapped onto a physical area not specific toeach MBSFN area. In a case in which other paging information is mappedonto a physical area not specific to each MBSFN area, it becomes able todetermine to which physical area the other paging information isallocated on the basis of the information about allocation of a pagingmessage mapped onto the physical area specific to each MBSFN area. Asthe method of multiplexing the paging signals destined for mobileterminals in the physical area specific to each MBSFN area, there is amethod of multiplying each of the paging signals or a CRC to be added toeach of the paging signals by the mobile-terminal-specificidentification number, as mentioned above. Each of the mobile terminalscan determine whether or not the paging signal is destined therefor andbecomes able to receive the paging signal by carrying out a correlationoperation with the mobile-terminal-specific identification number.Accordingly, because each of the mobile terminals has only to receivethe physical area of only the MBSFN area which is providing the MBMSservice which each of the mobile terminals is receiving, and thereforedoes not have to receive any other physical area, there is provided anadvantage of being able to achieve low power consumption in each of themobile terminals.

As an alternative, the information showing the presence or absence of anincoming call which is included in the paging signal can be mapped notto the physical area specific to each MBSFN area, but to a physical areaspecific to each MBSFN synchronization area. In this case, the sameadvantage as that as mentioned above can be provided. In this case, anMBSFN synchronization area specific number (an MBSFN synchronizationarea ID) can be used instead of the MBSFN-area-specific number. Aphysical area within MBSFN subframes (e.g., a frequency domain #m of asymbol #n) is determined as a concrete example of the physical areaspecific to each MBSFN synchronization area. By determining the physicalarea specific to each MBSFN synchronization area in this way, the pagingsignal can be mapped onto the physical area which is common within MBSFNsubframes of each MBSFN area (e.g., a frequency domain #m of a symbol#n). As a result, there is no necessity to determine the physical areaonto which the paging signals are mapped for each MBSFN area, and whatis necessary is just to determine one physical area for each MBSFNsynchronization area. Therefore, there is provided an advantage of beingable to simplify the method of deriving this physical area used by thenetwork side, the base station, and each mobile terminal, and to reducetheir circuit scales.

This embodiment is applied not only to the case in which the PMCHs ofMBSFN areas are configured in such a way as to be code divisionmultiplexed, but also a case in which the PMCHs of MBSFN areas areconfigured in such a way as to be time division multiplexed, and a casein which both time division multiplexing and code division multiplexingare applied to the PMCHs of MBSFN areas.

Each of the mobile terminals needs to know if the paging signal destinedfor the mobile terminal itself is mapped onto the DPCH of an MBSFN frameor an MBSFN subframe at what time. As a method of enabling each of themobile terminals to know if the paging signal destined for the mobileterminal itself is mapped onto the DPCH of an MBSFN frame or an MBSFNsubframe at what time, a predetermined method can be used to derive theMBSFN frame or MBSFN subframe. The MBSFN frame or MBSFN subframe can beinformed, as broadcast information, to each mobile terminal from theserving cell using a unicast service or the MBMS dedicated cell via anupper layer. The time can be periodic. Because the paging signal istransmitted at certain periods (or cycles), during a time period duringwhich this paging signal is not transmitted, the mobile terminal cancarry out a discontinuous reception operation when not receiving anyMBMS service. Therefore, the power consumption of each of the mobileterminals can be reduced.

As a result, because each of the mobile terminals becomes able to carryout blind detection of whether or not it is information destined for themobile terminal itself by using the identification code specific to themobile terminal or the scrambling code, it becomes unnecessary to fixthe physical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, there is no necessityto provide a physical area used for paging signals destined for all themobile terminals, and a physical area which is large enough to mappaging signals destined for a certain number of mobile terminals foreach of which an incoming call is predicted to actually occur has onlyto be provided. By using this method, it becomes able to use the limitedamount of physical resources effectively. In the above-mentionedexample, the base station multiplies the paging signal destined for eachof the mobile terminals by a mobile-terminal-specific identificationnumber. As an alternative, the base station can use a method ofmultiplying a CRC, instead of the paging signal, by amobile-terminal-specific identification number. The method ofmultiplying a CRC by a mobile-terminal-specific identification number iseffective for a case in which the amount of information of the pagingsignal destined for each of the mobile terminals differs.

The case in which only the paging indicator for informing the presenceor absence of an incoming call is provided as the paging information tobe transmitted by using the paging dedicated channel is described above,though the information about allocation of a paging message can beprovided as another concrete example of the paging information to betransmitted by using the paging dedicated channel. It can be used whenthe paging information needs to be transmitted as information other thanthe information for informing the presence or absence of an incomingcall. The presence or absence of an incoming call can be informed toeach mobile terminal with the information about allocation of a pagingmessage. As a result, when a mobile terminal receives the informationabout allocation of a paging message to the mobile terminal itself, themobile terminal can judge that paging is occurring. As an example of theinformation about allocation of a paging message, information showing aphysical area onto which, for example, a paging message transmitted viathe same subframe is mapped can be provided. The paging message ispaging information too, and is transmitted while being mapped onto thepaging dedicated channel. By thus defining the information about thephysical area as the allocation information, the mobile terminal whichhas received the information about allocation of a paging message hasonly to receive only this physical area in order to receive the pagingmessage, and therefore does not have to receive any other physical area.Therefore, the mobile terminal's power consumption at the time ofreceiving the paging message can be reduced. Furthermore, it becomesunnecessary to transmit beforehand the information about the physicalarea to which the paging signal is allocated to the mobile terminal viabroadcast information or the like, and the amount of signaling can bereduced. Furthermore, because it becomes able to carryout the allocationof the paging signal to the physical area with flexibility, there isprovided an advantage of improving the use efficiency of the radioresources.

In the case of using the method, disclosed in Embodiment 7, of carryinga paging signal onto the PMCH of each MBSFN area, the frequency withwhich the PMCH onto which a paging signal can be mapped is transmitteddecreases in time. Therefore, there arises a problem that paging signalsdestined for a large number of mobile terminals or all mobile terminalshave to be mapped onto the PMCH which is transmitted once and onto whichthe paging signals are mapped. In order to solve this problem, inEmbodiment 7, the paging grouping method and so on are disclosed. Inaccordance with this Embodiment 8, the above-mentioned problem can besolved by disposing a physical channel dedicated to paging which istransmitted via a multi-cell transmission scheme in an MBSFN area, andcarrying paging signals onto this physical channel. Furthermore, becausethe mobile communication system can transmit a paging signal destinedfor a mobile terminal which is receiving or trying to receive an MBMSservice from an MBMS dedicated cell, the mobile terminal becomes able toreceive the paging signal in the MBMS dedicated cell.

In the example shown in this Embodiment, a certain cell is configured insuch a way that a part of MBSFN subframes corresponding to the MBSFNarea to which this cell belongs is defined as a physical channeldedicated to paging (also referred to as a DPCH), and the DPCH isdisposed in each subframe. Instead of transmitting the DPCH everysubframe, the DPCH can be transmitted periodically. For example, theDPCH can be transmitted every two subframes, the DPCH can be transmittedevery radio frame, or a part of MBSFN subframes corresponding to eachMBSFN area can be transmitted as the physical channel dedicated topaging (also referred to as the DPCH). On the basis the number of mobileterminals to which paging can be transmitted simultaneously, the numberof mobile terminals depending upon the number of mobile terminals whichis taken into consideration by the system, and the frequency of paging,the repetition period of the transmission of the paging as the DPCH ofeach MBSFN area can be determined. As a result, subframes via which theDPCH is not transmitted can be defined as a data region for MBMSservice, and MBMS services can be speeded up.

Embodiment 9

In Embodiment 8, the method of disposing a physical channel dedicated topaging which is transmitted via a multi-cell transmission scheme in anMBSFN (Multimedia Broadcast multicast service Single Frequency Network)area, and carrying a paging signal onto this physical channel isdisclosed. Hereafter, in Embodiment 9, a method of disposing a physicalchannel which is transmitted via a multi-cell (multi cell) transmissionscheme in an MBSFN synchronization area, and carrying a paging signalonto this physical channel is disclosed.

FIG. 46 is an explanatory drawing showing the structure of a physicalchannel (referred to as a main PMCH) which is transmitted via amulti-cell transmission scheme in an MBSFN synchronization area. A casein which both time division multiplexing and code division multiplexingare applied to a PMCH disposed for each MBSFN area is shown. A cell #n1is one located in an MBSFN area 1, a cell #n2 is one located in an MBSFNarea 2, and a cell #n3 is one located in an MBSFN area 3. Furthermore,the cells #1, #2, and #3 also belong to an MBSFN area 4. Code divisionmultiplexing of the PMCHs of the MBSFN areas 1, 2, and 3 is carried out,and time division multiplexing of the PMCHs of the MBSFN areas 1, 2, and3 and the PMCH of the MBSFN area 4 is carried out. Time divisionmultiplexing of the main PMCH and the PMCH of each MBSFN area is carriedout. In the cell #n1, time division multiplexing of the PMCH1 and thePMCH4 is carried out and time division multiplexing of the main PMCH andthem is further carried out because the cell #n1 belongs to the MBSFNarea 1 and the MBSFN area 4. The same goes for each of the cells #2 and#3. Because the main PMCH is transmitted via a multi-cell transmissionscheme in the MBSFN synchronization area, it is transmitted on an MBSFNsubframe which is SFN-combined. A set of MBSFN frames to which MBSFNsubframes are allocated is referred to as an “MBSFN frame cluster”. Inan MBMS dedicated cell, all subframes in an MBSFN frame can be MBSFNsubframes used for multi-cell transmission. The length of each of therepetition periods at which the main PMCH is repeated is referred to asthe “main PMCH repetition period” (main PMCH repetition period). An MCHwhich is a transport channel for MBMS is mapped onto the main PMCH.Either or both of an MCCH which is a logical channel used fortransmission of MBMS control information and an MTCH which is a logicalchannel used for transmission of MBMS data are mapped onto the MCH. TheMCCH and the MTCH can be divided in time and mapped onto the main PMCH,or can be divided in time and mapped onto a physical area which istransmitted via a multi-cell transmission scheme.

For example, the MCCH and the MTCH can be mapped onto different MBSFNsubframes which are the physical area onto which they are finallymapped. The MCCH can be mapped onto MBSFN frame clusters via which themain PMCH is transmitted, or only the MTCH can be mapped onto the MBSFNframe clusters. In a case in which only the MTCH exists in the mainPMCH, the repetition period of the MCCH differs from the repetitionperiod of the main PMCH. Furthermore, there is a case in which aplurality of MCCHs are mapped onto the MBSFN frame clusters via whichthe main PMCH is transmitted. The length of each of the repetitionperiods at which the MCCH is repeated is expressed as the “MCCHrepetition period” (MCCH Repetition period). In FIG. 46, the MCCH1 (orthe MCCH2, 3, or 4) transmits MBMS control information for the MBSFNarea 1 (or the MBSFN area 2, 3, or 4), and the MTCH1 (or the MTCH2, 3,or 4) transmits MBMS data for the MBSFN area 1 (or the MBSFN area 2, 3,or 4). The MCCHs can be mapped onto the PMCHs respectively, or only theMTCHs can be mapped onto the PMCHs respectively. In the case in whichonly the MTCHs exist on the PMCHs respectively, the MCCH of each MBSFNarea can be mapped onto the main PMCH. As an alternative, the MCCH ofeach MBSFN area can be included as an information element of the MCCHmapped onto the main PMCH. Because the main PMCH is transmitted via amulti-cell transmission scheme in the MBSFN synchronization area, themain PMCH cannot be multiplied by an MBSFN-area-specific scrambling code(Scrambling Code), like the PMCH of each MBSFN area. This is because themain PMCH is transmitted from a cell in a different MBSFN area at thesame time, and therefore, when the main PMCH is multiplied by anMBSFN-area-specific scrambling code, the phase of this main PMCHtransmitted from each MBSFN area becomes random in the receiver of eachmobile terminal, and the receiver becomes unable to carry out SFNcombining of the main PMCH. Therefore, as shown above, by carrying outtime division multiplexing of the main PMCH and the PMCH of each MBSFNarea, the multiplication by the scrambling code specific to each MBSFNarea can be carried out on a per subframe basis while the multiplicationof only the main PMCH by the scrambling code specific to each MBSFN areacan be avoided. As a result, the main PMCH can be transmitted via amulti-cell transmission scheme in the MBSFN synchronization area, and,even if each mobile terminal is receiving or trying to receive any MBMSservice in this MBSFN synchronization area, the mobile terminal canreceive the main PMCH and can also acquire an SFN gain. The main PMCH isnot multiplied by the scrambling code specific to each MBSFN area, asmentioned above, though the main PMCH can be multiplied by the MBSFNsynchronization area specific scrambling code. In this case, theinterference from any cell in any other MBSFN synchronization area canbe suppressed, and receive errors detected in the MBMS service receivedby each mobile terminal can be reduced.

FIG. 47 is an explanatory drawing showing the configuration of a radioframe via which the main PMCH is transmitted. In FIG. 47, the subframesvia which the main PMCH is transmitted are the ones #k1 to #k2 (thenumbers k1 to k2 are neither 1 nor 5) excluding the subframes #0 and #5.It has been examined that in an MBMS dedicated cell, a synchronizationchannel (Synchronization Channel: SCH) is transmitted via the subframes#0 and #5 in one radio frame. It has been also examined that a broadcastchannel (Broadcast Channel: BCH) is transmitted via the subframe #0. Ithas been considered that either a cell specific sequence or anMBSFN-area-specific sequence is included in the synchronization channel(SCH), and the broadcast channel (BCH) is multiplied by either a cellspecific scrambling code or an MBSFN-area-specific scrambling code.Therefore, by selecting, as the subframes via which the main PMCH istransmitted, the ones excluding the subframes #0 and #5, the main PMCHcan be transmitted via a multi-cell transmission scheme in the MBSFNsynchronization area, and, even if each mobile terminal is receiving ortrying to receive any MBMS service in this MBSFN synchronization area,the mobile terminal can receive the main PMCH and can also acquire anSFN gain. In the example shown in the figure, the subframes via whichthe main PMCH is transmitted are continuous, though they can bediscontinuous. By selecting the continuous subframes excluding thesubframes #0 and #5, during a time period during which each mobileterminal does not have to receive any other subframes, the mobileterminal can carry out a discontinuous reception operation, therebybeing able to reduce the power for receiving. The main PMCH does nothave to be transmitted on a per radio frame basis. For example, the mainPMCH can be transmitted periodically, e.g., every two radio frames orevery ten radio frames. The length of each of the repetition periods atwhich the main PMCH is repeated is referred to as the “main PMCHrepetition period” (main PMCH repetition period). As a result, the PMCHin subframes via which the main PMCH is not transmitted can be definedas a data area for MBMS service, and MBMS services can be speeded up.The radio frame in which the main PMCH exists, the start timing (the SFNand the starting point) of the subframes, the subframe numbers, and themain PMCH repetition period length can be informed via broadcastinformation from the serving cell using a unicast service, can beinformed via broadcast information from the MBMS dedicated cell, or canbe predetermined. Because the main PMCH is transmitted via a multi-celltransmission scheme, the subframes in which the main PMCH exists can beMBSFN subframes and the radio frame in which the main PMCH exists is anMBSFN frame.

FIG. 48 is an explanatory drawing showing the configuration of a radioframe via which the main PMCH is transmitted within the same subframesas those within which the synchronization channel SCH exists. In FIG.48, the configuration in which the subframe via which the main PMCH istransmitted is the one #5, and the main MCH is mapped onto an area otherthan an area onto which the synchronization channel SCH is mapped isshown. In FIG. 47, the configuration in which the main PMCH is mappedonto the subframes excluding the subframes #0 and #5 is shown. As aresult, all the OFDM symbols in the subframes can be transmitted via amulti-cell transmission scheme in the MBSFN synchronization area.Therefore, the transmitter of the base station and the receiver of eachmobile terminal can be simplified. In FIG. 48, the main PMCH is formedin all or part of the area of the subframe #5 excluding the physicalarea of the subframe #5 onto which the synchronization channel SCH ismapped. As previously mentioned, the synchronization channel SCH istransmitted via the subframes #0 and #5 in one radio frame in the MBMSdedicated cell. In this case, because the broadcast channel BCH is nottransmitted via the subframe #5, it is not necessary to multiply thebroadcast channel BCH by either a cell specific scrambling code or anMBSFN-area-specific scrambling code. Therefore, all or part of the areaof the subframe #5 excluding the physical area of the subframe #5 ontowhich the synchronization channel SCH is mapped can be used for the mainPMCH. For example, in a case in which the SCH is mapped onto the 6th and7th OFDM symbols of the subframe #5, the 1st to 5th OFDM symbols and 8thto last OFDM symbols are defined as the area used for the main PMCH. Bydoing in this way, the main PMCH can be transmitted via a multi-celltransmission scheme in the MBSFN synchronization area, and, even if eachmobile terminal is receiving or trying to receive any MBMS service inthis MBSFN synchronization area, the mobile terminal can receive themain PMCH and can also acquire an SFN gain. By making it possible to usethe subframe #5 also for the main PMCH, the flexibility of the systemcan be improved and the efficiency of the radio resources can also beimproved.

FIG. 49 is an explanatory drawing showing the configuration of the mainPMCH in which an area for a paging signal is disposed. FIG. 49(a) is aview showing the configuration of the main PMCH including MBMS-relatedinformation and a paging signal thereon. The MBMS-related informationand the paging signal can exist as information elements in an MTCH andan MCCH respectively, or time division multiplexing of physical areas(resources) onto which the MBMS-related information and the pagingsignal are mapped respectively can be carried out. As a mapping methodin the case of carrying the MBMS-related information and the pagingsignal on the MTCH and the MCCH respectively as information elements,the method disclosed in FIG. 53 can be applied as an example. In thiscase, the physical channel PMCH shown in FIG. 53 can be assumed to bethe main PMCH. The paging signal as well as MBMS control informationincluded in the MBMS-related information are mapped onto the logicalchannel MCCH as information elements. The MCCH as well as the MTCH aremapped onto a multicast channel (MCH) which is a transport channel, andthe MCH is mapped onto the main PMCH which is a physical channel. Thus,a mobile terminal which is receiving or trying to receive an MBMSservice is enabled to receive the paging signal when receiving the MCCH.In another example, the method disclosed in FIG. 54 can be applied. Inthis case, the PMCH shown in FIG. 54 which is a physical channel can beassumed to be the main PMCH. The logical channel PCCH onto which thepaging signal is mapped are multiplexed with the logical channels MTCHand MCCH onto which the MBMS-related information is mapped, and themultiplexed channels are mapped onto the transport channel MCH. The basestation can provide an MBSFN subframe onto which only the MTCH ismapped, and an MBSFN subframe onto which the MCCH and the PCCH aremapped. The base station can also control to provide an MBSFN subframeonto which only the MCCH is mapped, and an MBSFN subframe onto whichonly the PCCH is mapped. By doing in this way, the base station cantransmit them separately in time from one another. Furthermore, an MBSFNsubframe onto which the MCCH is mapped and an MBSFN subframe onto whichthe PCCH is mapped can be arranged in such a way as to be adjacent toeach other in time. Thus, a mobile terminal which is receiving or tryingto receive an MBMS service is enabled to receive the paging signal whenreceiving the MCCH.

In a further example, the method disclosed in FIG. 55 can be applied. Inthis case, the physical channel PMCH shown in FIG. 55 can be assumed tobe the main PMCH. The PCCH onto which the paging signal is mapped ismapped onto the transport channel PCH, and this transport channel PCH ismultiplexed with the MCH and the multiplexed channels are mapped ontothe main PMCH. By doing in this way, the base station can transmit thePCH and the MCH separately in time from each other, and can furtherperform encoding on them independently from each other. Therefore, eachmobile terminal can decode the PCH and the MCH independently at the timeof reception of them. The above-mentioned example differs fromEmbodiment 7 in that the MTCH, MCCH, and PCCH which are mapped onto themain PMCH are transmitted via a multi-cell transmission scheme not in anMBSFN area but in an MBSFN synchronization area. Therefore, the PMCHtransmitted via a multi-cell transmission scheme in an MBSFN area, andthe main PMCH transmitted via a multi-cell transmission scheme in anMBSFN synchronization area can be separated clearly from each other.FIG. 57 is an explanatory drawing showing a mapping method in the caseof disposing the main PMCH as a physical channel common to MBSFNsynchronization areas. Mapping in the case of disposing the PMCH and themain PMCH is disclosed in FIG. 57. In this example, a case in which theMCH and PCH shown in FIG. 55 are used is shown. The MTCH and MCCH whichare MBMS-related information transmitted to the MBSFN area are mappedonto the transport channel MCH, and this transport channel MCH is mappedonto the physical channel PMCH. The PMCH is transmitted via an MBSFNsubframe corresponding to the MBSFN area. The MTCH and MCCH which areMBMS-related information transmitted to the MBSFN synchronization areaare mapped onto the transport channel MCH, and this transport channelMCH is mapped onto the main PMCH which is a physical channel. The PCCHonto which the paging signal transmitted to the MBSFN synchronizationarea is mapped is mapped onto the transport channel PCH, and thistransport channel PCH is mapped onto the main PMCH which is a physicalchannel. The main PMCH is transmitted via an MBSFN subframe transmittedvia a multi-cell transmission scheme in the MBSFN synchronization area.

Furthermore, the logical channel and/or the transport channel can bedisposed for each of the MBSFN area and the MBSFN synchronization area.For example, a case in which the MBMS-related information transmitted tothe MBSFN synchronization area is only the MBMS control information isshown by a dashed line of FIG. 57. For example, the logical channel MCCHtransmitted to the MBSFN synchronization area can be defined as a mainMCCH, and the transport channel MCH transmitted to the MBSFNsynchronization area can be defined as a main MCH. The main MCH ismapped onto the main PMCH which is a physical channel. By thus disposingthe logical channel and the transport channel for each of the MBSFN areaand the MBSFN synchronization area, the base station can carry outscheduling, a HARQ (Hybrid Automatic Repeat reQuest) process, anencoding process, an AMC (Adaptive Modulation Coding) process, etc.individually for each of the MBSFN synchronization area and the MBSFNarea. The system therefore becomes able to deal with variations in anradio wave environment between the base station and mobile terminalswith flexibility, and can improve the efficiency of the radio resources.The MCCH transmitted via a multi-cell transmission scheme in the MBSFNsynchronization area includes service information about services in eachMBSFN area included in the MBSFN synchronization area, and framestructure information. The MCCH can further include control informationfor MBMS service about each MBSFN area. In this case, because it is notnecessary to transmit the MCCH by using the PMCH of each MBSFN area, itbecomes able to enlarge the data area for MBMS, and can achieve animprovement in the speed of MBMS transmission. The MCCH transmitted viaa multi-cell transmission scheme in the MBSFN synchronization area isperiodically transmitted via a multi-cell transmission scheme in eachMBSFN synchronization area at the main PMCH repetition period (Main PMCHrepetition period).

On the other hand, a mobile terminal which is receiving or trying toreceive an MBMS service which is transmitted via a multi-celltransmission scheme from cells in an MBSFN area receives the MCCH on themain PMCH at regular intervals and also receives the contents of theMBMS service, information about the frame structure, etc., so that themobile terminal can receive the MBMS service. Therefore, after themobile terminal receives and decodes the MCCH on the main PMCH, whenthere is no desired service, the mobile terminal becomes able to carryout a discontinuous reception operation until it receives the next mainPMCH without receiving the PMCH corresponding to any other MBSFN area.Therefore, the power consumption of each mobile terminal can be reduced.In addition, by including the paging signal in this MCCH, a mobileterminal which is receiving or trying to receive an MBMS service isenabled to receive the paging signal when receiving the MCCH. As aresult, because the mobile terminal does not have to receive the pagingseparately at a time other than the time of receiving the MCCH, themobile terminal can receive the paging without interrupting thereception of the MBMS service. Furthermore, during a time period duringwhich the mobile terminal is not receiving the MCCH, and during a timeperiod during which the mobile terminal is not receiving the MBMSservice, the mobile terminal can carry out a discontinuous receptionoperation, thereby reducing its power consumption. In the case in whichthe method disclosed to FIG. 54 is applied, the MCCH and the PCCH can beconfigured in the same MBSFN subframe. As an alternative, an MBSFNsubframe onto which the MCCH is mapped and an MBSFN subframe onto whichthe paging signal is mapped can be arranged in such a way as to beadjacent to each other in time. In the case in which the methoddisclosed to FIG. 55 is applied, an MBSFN subframe onto which the MCCHis mapped and an MBSFN subframe onto which the paging signal is mappedcan be arranged in such a way as to be adjacent to each other in time.In the case in which they are configured in this way, a mobile terminalwhich is receiving or trying to receive an MBMS service is enabled toreceive the paging signal continuously when receiving the MCCH. As aresult, because the mobile terminal does not have to separately receivethe paging signal at a time other than the time of receiving the MBSFNsubframes onto which the MCCH and the PCCH are mapped, the mobileterminal can receive the paging signal without interrupting thereception of the MBMS service. Furthermore, during a time period duringwhich the mobile terminal is not receiving the MCCH, and during a timeperiod during which the mobile terminal is not receiving the MBMSservice, the mobile terminal can carry out a discontinuous receptionoperation, thereby reducing its power consumption.

In FIG. 49(b), a configuration in which an indicator 1 which is a“paging signal presence or absence indicator” indicating whether thepaging signal has been transmitted, an indicator 2 which is an“MBMS-related information modified or unmodified indicator” indicatingwhether or not the MBMS control information has been changed areprovided is disclosed. A physical area onto which the indicators aremapped can be disposed in an MBSFN subframe via which the main PMCH istransmitted. As an alternative, a physical area onto which theindicators are mapped can be the one adjacent in time to an MBSFNsubframe via which the main PMCH is transmitted. By configuring thephysical area onto which the indicators are mapped in this way, eachmobile terminal can receive and decode the MCCH and the paging signalwhich are mapped onto the main PMCH immediately after receiving theindicators. For example, 1-bit information is defined as each of theindicators. Each of the indicators is encoded or multiplied by an MBSFNsynchronization area specific scrambling code, and is mapped onto apredetermined physical area. For example, when an incoming call to amobile terminal is occurring, the corresponding paging signal presenceor absence indicator is set to “1”, whereas when no incoming call to themobile terminal is occurring, the paging signal presence or absenceindicator is set to “0”. Furthermore, for example, when the MBMS controlinformation which is mapped onto the MCCH has been changed due to achange in the contents of the MBMS service transmitted in the MBSFNsynchronization area, or the like, the MBMS-related information modifiedor unmodified indicator is set to “1”. The length of a time period(referred to as an MBMS modification period) during which theMBMS-related information can be modified is determined, and theMBMS-related information modified or unmodified indicator “1” istransmitted repeatedly within the MBMS modification period. The lengthof the time period (the MBMS modification period) during which theMBMS-related information can be modified, the start timing (the SFN andthe starting point), etc. can be predetermined. As an alternative, theycan be informed via broadcast information from either the serving cellusing a unicast service or the MBMS dedicated cell. When there is nofurther modification in the MBMS-related information after theexpiration of the above-mentioned time period (the MBMS modificationperiod), the MBMS-related information modified or unmodified indicatoris set to “0”.

Each mobile terminal can determine whether or not there is amodification in the MBMS-related information which exists in the MCCHand whether or not the paging signal exists by receiving the indicatorsin either the MBSFN subframe via which the main PMCH is transmitted viaa multi-cell transmission scheme or another MBSFN subframe adjacent tothe MBSFN subframe, and performing de-spreading and the like on each ofthe indicators to determine whether or not each of the indicators is 1or 0. By thus disposing the indicators, when there is no modification inthe MBMS control information and when no paging signal exists, eachmobile terminal does not have to receive and/or decode all theinformation on the PMCH. Therefore, it becomes able to reduce the powerfor receiving of each mobile terminal. The physical area onto which theMBMS-related information modified or unmodified indicator indicatingwhether the MBMS control information has been modified is mapped can bethe first one of one or more MBSFN subframes onto which the MBMS controlinformation is mapped. As an alternative, the physical area onto whichthe MBMS-related information modified or unmodified indicator indicatingwhether the MBMS control information has been modified is mapped can bean OFDM symbol at the head of the above-mentioned first MBSFN subframe.As a result, each mobile terminal becomes able to determine whether amodification is occurring in the MBMS control information by receivingthe first OFDM symbol. Furthermore, the physical area onto which thepaging signal presence or absence indicator indicating whether or notthe paging signal exists is mapped can be the first one of one or moreMBSFN subframes onto which the paging signal is mapped. As analternative, the physical area onto which the paging signal presence orabsence indicator indicating whether or not the paging signal exists ismapped can be an OFDM symbol at the head of the above-mentioned firstMBSFN subframe. As a result, each mobile terminal becomes able todetermine whether or not the paging signal exists by receiving the firstOFDM symbol.

By mapping each indicator onto such a physical area as mentioned above,when there is no modification in the MBMS control information and whenno paging signal exists, each mobile terminal does not have to receiveand/or decode subsequent OFDM symbols. Therefore, it becomes able tofurther reduce the power for receiving of each mobile terminal.Furthermore, because each mobile terminal can determine whether there isno modification in the MBMS control information or whether the pagingsignal exists at an earlier time from the first MBSFN subframe or theOFDM symbol at the head of the first MBSFN subframe, each mobileterminal can receive the MBMS control information immediately or canreceive the paging signal immediately, it becomes able to reduce thecontrol delay time occurring in each mobile terminal. The MBMS-relatedinformation modified or unmodified indicator and the paging signalpresence or absence indicator can be mapped onto different physicalareas, or can be mapped onto different physical areas. In the case inwhich the indicators are mapped onto an identical physical area, what isnecessary is just to implement an OR logical operation on theindicators. As a result, each mobile terminal has only to receive asingle indicator, there is provided an advantage of being able tosimplify the receiving circuit configuration. In contrast, in the casein which the indicators are mapped onto different physical areas, eachmobile terminal has only to receive only a required one of theindicators without having to receive the other indicator. Therefore, thepower for receiving of each mobile terminal can be further reduced, andthe delay time occurring in the reception of the required informationcan be further reduced. For example, a mobile terminal which is set soas not to receive a paging signal while receiving an MBMS service hasonly to receive the MBMS-related information modified or unmodifiedindicator, and can eliminate the necessity to receive the paging signalpresence or absence indicator. The lengths of the repetition periods ofthe indicators can be the same as each other, or can be different fromeach other. The length of the repetition period of each of theindicators can be the same as that of the main PMCH, or can be differentfrom that of the main PMCH. For example, the MBMS-related informationmodified or unmodified indicator can be disposed in the main PMCH oncefor every plural times the main PMCH is transmitted. The lengths of therepetition periods of the indicators are referred to as the “pagingsignal presence or absence indicator repetition period” and the“MBMS-related modified or unmodified indicator repetition period”. Thestart timing (the SFN and the starting point) of the MBSFN subframe inwhich the indicators exist, the subframe number, the repetition periodlengths of the indicators, and so on can be informed via broadcastinformation from the serving cell using a unicast service, can beinformed via broadcast information from the MBMS dedicated cell, or canbe predetermined.

In addition, a channel intended for the MBMS-related informationmodified or unmodified indicator can be formed on the main PMCH. Forexample, the channel can be configured as an MICH (MBMS IndicatingCHannel). The paging signal presence or absence indicator is formed inthe MICH, and the length of the repetition periods at which the MICH isrepeated is referred to as the “MICH repetition period” (MICH Repetitionperiod). The length of the repetition period of the paging signalpresence or absence indicator can be the same as that of the MICH, orcan be different from that of the MICH. The notification of theindicator can be made by using the same method as that describedpreviously. As a result, the time when each of the indicators istransmitted is not limited to the time when the MCCH is transmitted, andtherefore it becomes able to design the system with flexibility. In thecase in which the indicators are configured as mentioned above, only thedetection of the above-mentioned indicators cannot clarify whether theMBMS service being transmitted in the desired MBSFN area has beenchanged because the MBMS-related information modified or unmodifiedindicator simply shows whether the MBMS control information on the mainPMCH has been changed. Each mobile terminal has to receive and decodethe MBMS control information on the main PMCH in order to know whetherthe MBMS service being transmitted in the desired MBSFN area has beenchanged. As the MBMS control information on the main PMCH, an indicatorshowing whether an MBMS service being transmitted in which MBSFN areahas been changed can be further disposed. A physical area used for thisindicator can be disposed just before the MBSFN subframe onto which theMBMS control information on the main PMCH is mapped. By providing theabove-mentioned indicator in this way, each mobile terminal can detectwhether the MBMS service being transmitted in the desired MBSFN area hasbeen changed without having to receive and decode all of the MBMScontrol information on the main PMCH. Therefore, it becomes able toreduce the control delay time occurring in each mobile terminal.

In a case in which the paging signal is mapped onto the PMCH, therearises a problem that when the number of mobile terminals for each ofwhich an incoming call is occurring becomes huge, it takes too much timefor each of the mobile terminals to detect the paging signal destinedfor the mobile terminal itself. A further problem is that any area ontowhich the paging signals for all the mobile terminals for each of whichan incoming call is occurring are to be mapped cannot be ensured in acertain physical area onto which the paging signals are to be mapped. Inorder to solve these problems, a method of carrying out paging groupingwill be disclosed hereafter. An example of the configuration of pagingsignal presence or absence indicators is shown in FIG. 49(c). All themobile terminals are divided into K groups, and a paging signal presenceor absence indicator is disposed for each of the groups. The physicalarea used for the paging signal presence or absence indicators isdivided into K parts, and the paging signal presence or absenceindicators of the K groups are mapped onto the K divided parts of thephysical area respectively. In this case, K can have a value rangingfrom 1 to the number of all the mobile terminals. When an incoming callto a mobile terminal is occurring, the paging signal presence or absenceindicator of the group to which this mobile terminal belongs is set to“1”. When no incoming call to any of all the mobile terminals belongingto a group is occurring, the paging signal presence or absence indicatorof this group is set to “0”. A repetition or the like of repeatedlymapping the same paging signal presence or absence indicator value of“1” (or “0”) onto the physical area can be carried out so that each ofthe mobile terminals satisfies a desired error rate of reception. Thephysical area onto which paging signals are mapped is also divided intoK parts, and these K parts are brought into correspondence with theabove-mentioned K groups respectively. As the paging signal destined foreach mobile terminal, an identifier of the mobile terminal (anidentification number or an identification code) can be provided. Eachof the K divided pieces of the physical area is the sum of thecorresponding group's mobile terminals' physical areas in each of whichpaging signal data required by one mobile terminal is accommodated. Thenumber of mobile terminals in each group can be identical to that in anyother group, or can be different from that in any other group. Thenumber of mobile terminals in each group is calculated by using, forexample, a method of calculating the average of measurements of thenumber of mobile terminals for each of which an incoming call hasoccurred simultaneously. As an alternative, a method of defining thenumber of mobile terminals which can be allocated to one OFDM symbol asthe number of mobile terminals in each group, and then bringing aplurality of OFDM symbols into correspondence with the plurality ofgroups respectively can be used.

When an incoming call to a mobile terminal is occurring, “1” is set tothe paging signal presence or absence indicator of the group to whichthis mobile terminal belongs, and the paging signal presence or absenceindicator is mapped onto the physical area corresponding to this groupand used for the paging signal presence or absence indicator. Inaddition, the paging signal destined for the mobile terminal for whichan incoming call is occurring is mapped onto the paging-related physicalarea corresponding to the group to which this mobile terminal belongs.The mapping of the paging signal to the physical area is carried out byusing a method of multiplying the paging signal destined for each mobileterminal by an identification code specific to the mobile terminal. Thepaging signal destined for each mobile terminal can be an identifier ofthe mobile terminal. In this case, the above-mentioned control operationof multiplying the paging signal destined for each mobile terminal bythe identification code specific to the mobile terminal can be omitted.Each mobile terminal determines whether an incoming call destined forthe group for which the mobile terminal itself belongs is occurring byreceiving the paging signal presence or absence indicator of the groupto which the mobile terminal itself belongs. When determining that anincoming call is occurring, each mobile terminal receives and decodesthe physical area onto which the paging signal brought intocorrespondence with the group onto which the mobile terminal belongs ismapped. After decoding the physical area, each mobile terminal carriesout an operation of calculating a correlation with the identificationcode specific to the mobile terminal to carry out blind detection tospecify the paging signal destined for the mobile terminal itself. As aresult, each mobile terminal becomes able to determine that an incomingcall to the mobile terminal itself is occurring. When each mobileterminal has not detected the paging signal destined therefor, themobile terminal itself determines that no incoming call thereto isoccurring. By grouping all the mobile terminals into the K groups, thenecessity for each of the mobile terminals to receive all of the areadedicated to paging signals can be eliminated, and each of the mobileterminals has only to receive only a required area, i.e., a physicalarea corresponding to the group to which the mobile terminal itselfbelongs. Therefore, it becomes able to reduce the power for receiving ofeach mobile terminal. In addition, by using the paging signal presenceor absence indicator corresponding to each group, also when there aremany mobile terminals, the paging signal presence or absence indicatorscan be provided with a small amount of physical resources. Furthermore,each of the mobile terminals has only to receive an area dedicated topaging signals as needed. Therefore, while the power for receiving ofeach of the mobile terminals can be reduced, the control delay time canalso be reduced because each of the mobile terminals can make atransition to the next operation immediately when it does not have toreceive the paging signal.

As the method of mapping an indicator showing whether or not a pagingsignal has been transmitted onto a physical area, the method of mappinga paging signal onto a physical area shown in Embodiment 7 can beapplied too. Furthermore, in this case, the base station can multiplythe indicator showing whether or not a paging signal has beentransmitted by a mobile-terminal-specific identification code (UE-ID orRNTI). Furthermore, the base station is configured in such a way as toadd a CRC to the indicator showing whether or not a paging signal hasbeen transmitted, and can also use a method of multiplying the CRC by amobile-terminal-specific identification number. As a result, each of themobile terminals becomes able to carry out blind detection of whether ornot it is information destined for the mobile terminal itself by usingthe mobile-terminal-specific identification code. Therefore, it becomesunnecessary to fix the physical area onto which the indicator showingwhether the paging signal destined for each of the mobile terminals hasbeen transmitted is mapped in advance. The physical area onto which thisindicator can be mapped can be predetermined, or can be broadcast. Bythus predetermining or broadcasting the physical area, the physicalresources can be used with flexibility. As will be mentioned below,these methods are effective for not a case in which the indicatorshowing whether a paging signal has been transmitted is 1-bitinformation, but a case in which the amount of information transmittedto each mobile terminal, such as information about allocation of apaging message, differs.

In above-mentioned Embodiment, each of the K divided pieces of thephysical area onto which paging signals are mapped is the sum of thecorresponding group's mobile terminals' physical areas in each of whichpaging signal data required by one mobile terminal is accommodated.However, because the required physical area becomes very large and theoverhead for transmitting the MBMS service increases greatly as thenumber of mobile terminals becomes huge, the transmission rate of theMBMS service data decreases. In order to prevent this problem, thepaging signal destined for each of the mobile terminals is multiplied byan identification code specific to the mobile terminal itself. As aresult, because each of the mobile terminals becomes able to carry outblind detection of whether or not it is information destined for themobile terminal itself by using the identification code specific to themobile terminal, it becomes unnecessary to fix the physical area ontowhich the paging signal destined for each of the mobile terminals ismapped in advance. Therefore, there is no necessity to provide aphysical area required for the paging signals destined for all themobile terminals, and a physical area which is large enough to mappaging signals destined for a certain number of mobile terminals foreach of which an incoming call is predicted to actually occur has onlyto be provided. As an example, there is a method of defining the averageof measurements of the number of mobile terminals for each of which anincoming call has occurred simultaneously as the number of mobileterminals to be included in each group. By using this method, it becomesable to use the limited amount of physical resources effectively.Furthermore, by using the above-mentioned method, the mobilecommunication system can flexibly deal with even a case in which thenumber of mobile terminals for each of which an incoming call isoccurring becomes larger than a predicted number through scheduling in abase station. For example, the mobile communication system can transmita paging signal destined for a mobile terminal receiving a new incomingcall on the next main PMCH.

When the number of all the mobile terminals is small, only the pagingsignal presence or absence indicators can be transmitted by setting thevalue of K to be equal to the number of all the mobile terminals. Inthis case, there is no necessity to ensure the physical area used forpaging signals, and what is necessary is just to ensure a physical areaused for the paging signal presence or absence indicators andcorresponding to the number of all the mobile terminals. Therefore, theefficiency of the radio resources can be improved. Furthermore, in thiscase, there exists a physical area used for a paging signal presence orabsence indicator and corresponding to each mobile terminal. Therefore,each of the mobile terminals can determine the presence or absence of anincoming call without receiving the area used for paging signals bysimply receiving and decoding the physical area for a paging signalpresence or absence indicator and corresponding to the mobile terminalitself, thereby being able to reduce the control delay time occurringwhen performing the paging operation.

Furthermore, in the above-mentioned example, the base station carriesout the process of multiplying the paging signal destined for each ofthe mobile terminals by an identification code specific to this mobileterminal. The base station can alternatively use another method ofadding the paging signal destined for each of the mobile terminals andan identification number specific to this mobile terminal. In this case,each of the mobile terminals can detect the paging signal destined forthe mobile terminal itself by determining whether themobile-terminal-specific identification number exists in the receivedinformation on which the mobile terminal itself has performed theprocess including decoding.

In this embodiment, the configuration of disposing the indicator showingwhether or not the paging signal has been transmitted is disclosed. Asan alternative, the information about allocation of the paging signalcan be provided as this indicator. As a result, when each mobileterminal receives the information about allocation of the paging signalto the mobile terminal itself, the mobile terminal can judge that pagingis occurring. As an example of the information about allocation of thepaging signal, information showing the physical area onto which thepaging signal transmitted via the same subframe, e.g., a paging messageis mapped can be provided. By thus defining the information about thephysical area as the allocation information, each mobile terminal whichhas received the information about allocation of the paging message hasonly to receive only this physical area in order to receive the pagingmessage, and therefore does not have to receive any other physical area.Therefore, each mobile terminal's power consumption at the time ofreceiving the paging message can be reduced. Furthermore, it becomesunnecessary to transmit beforehand the information about the physicalarea to which the paging signal is allocated to each mobile terminal viabroadcast information or the like, and the amount of signaling can bereduced. Furthermore, because it becomes able to carryout the allocationof the paging signal to the physical area with flexibility, there isprovided an advantage of improving the use efficiency of the radioresources.

As the method of mapping the paging signal onto the paging-relatedphysical area of the main PMCH, the method disclosed in Embodiment 7 canbe applied. For example, the method shown in FIG. 33 or 34 can beapplied. However, in the modulation process, the descrambling process,etc., the step of multiplying the result of the multiplexing by anMBSFN-area-specific scrambling code cannot be applied, and it isnecessary not to multiply the result of the multiplexing by anMBSFN-area-specific scrambling code, or it is necessary to multiply theresult of the multiplexing by an MBSFN synchronization area specificscrambling code.

As to a mobile-terminal-specific identification code which is used bythis embodiment, the same method as that described in Embodiment 7 isused. According to this embodiment, an identification code specific toeach MBSFN synchronization area is defined as a mobile-terminal-specificidentification code. The method of defining an identification codespecific to each MBSFN synchronization area as amobile-terminal-specific identification code is not limitedly applied tothis embodiment, and can be applied to a case of multiplying the resultof the multiplexing by a mobile-terminal-specific identification codewhen carrying out multi-cell (MC) transmission in an MBSFNsynchronization area. Two or more mobile-terminal-specificidentification codes can be defined for each MBSFN synchronization area.The two or more mobile-terminal-specific identification codes can be putto different uses. For example, two different mobile-terminal-specificidentification codes specific to each mobile terminal are provided foreach MBSFN synchronization area, and one of them is used for the pagingsignal and the other identification code is used for the MBMS controlinformation. By providing two different mobile-terminal-specificidentification codes in this way, the paging signal which is transmittedvia an MC transmission scheme in the MBSFN synchronization area isseparated into parts respectively destined for mobile terminals and eachof the mobile terminals can receive the paging signal destined for themobile terminal itself.

In the above-mentioned example, the methods disclosed in Embodiment 7are applied as the configuration of the main PMCH and the method ofmapping a paging signal onto the main PMCH. Similarly, in a case inwhich, for example, the frequency with which the main PMCH istransmitted is high in time, the methods disclosed in Embodiment 8 canbe applied as the configuration of the main PMCH and the method ofmapping a paging signal onto the main PMCH.

By using the method of disposing a physical channel transmitted via amulti-cell transmission scheme in the MBSFN synchronization area, andcarrying a paging signal on this physical channel, which is disclosedabove in this Embodiment 9, the mobile communication system can transmitthe paging signals destined for all mobile terminals each of which isreceiving or trying to receive an MBMS service from an MBMS dedicatedcell to make it possible for each of the above-mentioned mobileterminals to receive the paging signal from the MBMS dedicated cell.

Embodiment 10

In the above-mentioned embodiments, the method of providing a pagingsignal in such a way that the paging signal is transmitted via amulti-cell transmission scheme from all cells in either an MBSFN area oran MBSFN synchronization area is disclosed. It can be considered thateither an MBSFN area or an MBSFN synchronization area is a huge areageographically. In such a case, transmission of a paging signal destinedfor a mobile terminal from a cell which does not contribute to SFNcombining in the mobile terminal causes wasted radio resources and hencereduction in the system capacity. Therefore, there is a necessity tolimit the cells each of which transmits a paging signal to a mobileterminal to a cell in which the mobile terminal is being located, andneighboring cells. In the case of limiting the cells each of whichtransmits a paging signal to a mobile terminal to a cell in which themobile terminal is being located, and neighboring cells, a cell whichtransmits a paging signal to a mobile terminal and a cell which does nottransmit any paging signal to the mobile terminal exist within either anidentical MBSFN area or an identical MBSFN synchronization area, andsignals different between the cells are transmitted to the mobileterminal via a transmission scheme which is not a multi-celltransmission one. Because each mobile terminal cannot limit the cellsfrom each of which it receives a paging signal selectively, each mobileterminal also receives a signal which is not transmitted via amulti-cell transmission scheme and this results in a receive error beingcaused therein. A different signal transmitted from a cell which doesnot transmit any paging signal causes degradation in the quality ofreception of the desired paging signal. Particularly, a mobile terminalbeing located in the vicinity of a boundary between a cell whichtransmits a paging signal and a cell which does not transmit any pagingsignal has an increasing number of receive errors, and therefore has aproblem of becoming unable to receive the paging signal. Therefore, inaccordance with this embodiment, a configuration of providing both acell which transmits a paging signal and a cell which does not transmitany paging signal is disclosed.

In order to reduce receive errors occurring in each mobile terminal whenreceiving a paging signal, the method of mapping a paging signal ischanged between a cell which transmits a paging signal, and a cell whichdoes not transmit any paging signal. FIG. 50 is an explanatory drawingshowing a method of transmitting a paging signal to some cells in eitheran MBSFN area or an MBSFN synchronization area. As shown in FIG. 50, ina cell which transmits a paging signal, a base station multiplies asignal by an identification number specific to a mobile terminal inquestion (process 1), adds a CRC to the result of the multiplication(process 2), and carries out a process including encoding and ratematching (process 3), as explained with reference to FIG. 33 or 44. Thebase station then allocates the result of the series of processes whichit has carried out to a control information element unit (process 8),and carries out a process of connecting a plurality of controlinformation elements whose number is equal to that of mobile terminalsfor each of which an incoming call is occurring to one another. Incontrast, in a cell which does not transmit any paging signal, a basestation does not carry out the above-mentioned processes. As a physicalarea onto which the paging signal is mapped, there are a PMCH, a DPCH,or a main PMCH as shown in the above-mentioned embodiments. In a case inwhich a cell which transmits a paging signal to a mobile terminal forwhich an incoming call is occurring, and a cell which does not transmitany paging signal to the mobile terminal exist within either an MBSFNarea or an MBSFN synchronization area, a base station connects a switch2401 thereof shown in the figure to a terminal a in the cell whichtransmits a paging signal to the mobile terminal. The base station thenmultiplies the paging signal to the mobile terminal by an identificationnumber specific to the mobile terminal, adds a CRC to the result of themultiplication, and carries out a process including encoding and ratematching. Because the switch 2401 is connected to the terminal a,information processed as above for each mobile terminal is allocated toa control information element unit.

In the above-mentioned example, the paging signal destined for each ofthe mobile terminals is allocated to a control information element unithaving a size corresponding to the size of the physical area onto whichthe paging signal is to be mapped. As an alternative, the paging signaldestined for each of the mobile terminals can be allocated to atransport block unit. In the case in which the paging signal destinedfor each of the mobile terminals is allocated to a transport block unit,the physical resource to which the paging signal is allocated can beincreased or decreased according to the amount of information, and theallocation to the physical area can be carried out with flexibility.

In contrast, in the cell which does not transmit any paging signal, abase station connects a switch 2401 thereof shown in the figure to aterminal b. A code for padding for each cell is provided without usingthe paging signal destined for each mobile terminal, and this code forpadding is allocated to a control information element unit. In thiscase, the area of a control information element unit allocated to amobile terminal is the same for both the cell which transmits a pagingsignal and the cell which does not transmit any paging signal.Accordingly, each base station can easily switch between pieces ofinformation to be allocated by using the switch in the cell whichtransmits a paging signal and the cell which does not transmit anypaging signal. In addition, by making the size of the area of a controlinformation element unit allocated to a mobile terminal be equal foreach of all the mobile terminals, the length of the code for paddingdefined for each cell can be predetermined. As a result, a controloperation of embedding the code for padding can be simplified. Incontrast, a mobile terminal which is receiving or trying to receive anMBMS service transmitted via a multi-cell transmission scheme from cellsin either an MBSFN area or an MBSFN synchronization area receives aPMCH, a DPCH, or a main PMCH onto which a paging signal destinedtherefor is mapped, carries out a demodulation process, a descrambling,and so on, and divides the result of the demodulation and descramblinginto parts each corresponding to a control information element unit. Themobile terminal then carries out blind detection of the paging signaldestined for the mobile terminal itself by performing a processincluding decoding on each of the divided parts each corresponding to acontrol information element unit, and then carrying out an operation ofcalculating a correlation with an identification number specific to themobile terminal. When the result of the correlation operation is largerthan a certain threshold, the mobile terminal determines that there ispaging destined for the mobile terminal itself, and starts an operationof receiving a paging incoming call with the paging signal. In contrast,when the result of the correlation operation is equal to or smaller thanthe certain threshold, the mobile terminal determines that there is nopaging destined for the mobile terminal itself, and makes a transitionto reception of MBMS-related information or makes a transition to adiscontinuous reception operation if there is no necessity to receiveany MBMS-related information.

When a transmission signal from the cell which does not transmit anypaging signal differs from a transmission signal from the cell whichtransmits a paging signal, the transmission of these transmissionsignals is not multi-cell transmission and no SFN gain can be obtainedfrom multi-cell transmission, while the transmission signal from thecell which does not transmit any paging signal acts as noise and anincreasing number of errors occurs in the correlation operation resultin each mobile terminal. As disclosed in this embodiment, bypredetermining a code for padding (embedding or setting) in a cell whichdoes not transmit any paging signal, and then embeds this code forpadding to an area onto which the paging signal destined for each mobileterminal is mapped, errors occurring in the correlation operation byeach mobile terminal can be reduced. FIG. 51 is an explanatory drawingshowing an example of the code for padding for each cell which isdisposed in a cell which does not transmit any paging signal. Forexample, in a cell which does not transmit any paging signal, the codefor padding is set to “all 0s” (all 0s). In this case, in all cells eachof which does not transmit any paging signal, the same code, i.e., thecode set to “all 0s” is provided. By providing the code for padding inthis way, each mobile terminal can cancel components of “0” transmittedfrom a cell which does not transmit any paging signal by using aninterference elimination function, such as an interference canceller, inthe receiver thereof, becomes able to carry out SFN combining of onlythe paging signal transmitted from a cell which transmits the pagingsignal, and can therefore reduce receive errors occurring in the pagingsignal in the correlation operation carried out thereby. As analternative, in a cell which does not transmit any paging signal, thecode for padding is set to “all 1s” (all 1s). In this case, in all cellseach of which does not transmit any paging signal, the same code, i.e.,the code set to “all 1s” is provided. Also in this case, each mobileterminal can cancel components of “1” transmitted from a cell which doesnot transmit any paging signal by using an interference eliminationfunction, such as an interference canceller, and can therefore reducereceive errors occurring in the paging signal received thereby. In eachcell which does not transmit any paging signal, the code for padding canbe alternatively set to a known specific code other than all 0s and all1s. The code for padding in each cell which does not transmit any pagingsignal can be alternatively set to a random value. In this case, arandom value is derived for each cell, and padding with this randomvalue is carried out. By configuring the code for padding in this way,because the signals transmitted from cells each of which does nottransmit any paging signal are random signals which differ from oneanother, they are canceled out in each mobile terminal and therefore thepaging signal component transmitted from the cell which transmits thepaging signal becomes strong relatively. Therefore, it becomes able toreduce receive errors occurring in the paging signal in the correlationoperation.

A code for paging transmission cell identification can be used fordistinguishing between the cell which transmits a paging signal and thecells each of which does not transmit any paging signal. The code forpaging transmission cell identification can be an orthogonal code or apseudo orthogonal code. As an alternative, the code for pagingtransmission cell identification can be a scrambling code or ascrambling code. FIG. 52 is an explanatory drawing showing a method ofusing the code for paging transmission cell identification. The basestation multiplies the paging signal by a code for mobile terminalidentification (process 1), carries out a coding (Coding) processincluding CRC addition, encoding, rate matching, and MCS (ModulationCoding Scheme) reflection (process 2), and multiplies the result of theprocess by the code for paging transmission cell identification (process3). As the code for paging transmission cell identification, ascrambling code for paging signal transmission cell is used in the cellwhich transmits a paging signal. In each of the cells which does nottransmit any paging signal, a scrambling code for paging signaluntransmission cell is used as the code for paging transmission cellidentification. The scrambling code for paging signal transmission cellidentification and the scrambling code for paging signal untransmissioncell, which are the codes for paging transmission cell identification,are orthogonal to each other. A process of allocating the result of themultiplication by each of these codes for paging transmission cellidentification to a control information element unit, and connecting aplurality of control information elements whose number is equal to thatof mobile terminals for each of which an incoming call is occurring toone another is carried out (process 4). In contrast, a mobile terminalwhich is receiving or trying to receive an MBMS service transmitted viaa multi-cell transmission scheme from cells in either a certain MBSFNarea or an MBSFN synchronization area receives a PMCH, a DPCH, or a mainPMCH onto which a paging signal destined therefor is mapped, carries outa demodulation process, a descrambling, and so on, and divides theresult of the demodulation and descrambling into parts eachcorresponding to a control information element unit. The mobile terminalthen performs descrambling on each of the divided parts eachcorresponding to a control information element unit by using thescrambling code for paging signal transmission cell. Because thetransmission signals are transmitted after they have been multiplied, inthe same physical area, by the scrambling codes, which are orthogonal toeach other, by both the cell which transmits the paging signal and eachof the cells which does not transmit any paging signal, the mobileterminal becomes able to eliminate the influence of the transmissionsignal from each of the cells which does not transmit any paging signalby carrying out the descrambling by using the scrambling code for pagingsignal transmission cell, and therefore can reduce the occurrence ofreceive errors.

The mobile terminal then carries out blind detection of the pagingsignal destined for the mobile terminal itself by using theidentification code specific to the mobile terminal itself by performinga process including decoding on the descrambled data. When the result ofthe correlation operation is larger than a certain threshold, the mobileterminal determines that there is paging destined for the mobileterminal itself, and starts an operation of receiving a paging incomingcall with the paging signal. In contrast, when the result of thecorrelation operation is equal to or smaller than the certain threshold,the mobile terminal determines that there is no paging destined for themobile terminal itself, and makes a transition to reception ofMBMS-related information or makes a transition to a discontinuousreception operation if there is no necessity to receive any MBMS-relatedinformation. Each of the codes for paging transmission cellidentification can be predetermined, or can be informed via broadcastinformation of an MBMS dedicated cell or broadcast information of anunicast cell. By thus multiplying transmission signals by the scramblingcodes, which are orthogonal to each other, in the cell which transmits apaging signal and each of the cells which does not transmit any pagingsignal, and making the receive side carry out the descrambling on them,the influence of the signal from each of the cells which does nottransmit any paging signal can be eliminated, and it becomes able toextract the paging signal from the cell which transmits the pagingsignal with a lower number of receive errors. In the present invention,the order in which the multiplication by the code for mobile terminalidentification and the multiplication by the code for pagingtransmission cell identification are carried out can be reversed. In acase in which the multiplication by the code for mobile terminalidentification is carried out after the multiplication by the code forpaging transmission cell identification, the mobile terminal carries outan operation of calculating a correlation with the identification numberspecific to the mobile terminal itself previously, thereby providing anadvantage of becoming able to determine whether there is a paging signaldestined for the mobile terminal itself at an earlier time.

In the above-mentioned example, the process of multiplying the pagingsignal destined for each of the mobile terminals by the identificationcode specific to the mobile terminal itself in the process 1 disclosedwith reference to FIGS. 50 and 52 is carried out. The base station canalternatively use another processing method of adding the paging signaldestined for each of the mobile terminals and an identification numberspecific to this mobile terminal. In this case, each of the mobileterminals receives the physical area used for the paging signal, carriesout demodulation and descrambling using an MBSFN-area-specificscrambling code, and divides the result of the demodulation anddescrambling into parts each corresponding to an information elementunit, and performs a process including decoding on each of the dividedparts each corresponding to an information element unit. Each of themobile terminals then determines whether the mobile-terminal-specificidentification number exists in the information on which the mobileterminal itself has performed the process including decoding to detectthe paging signal destined therefor.

In this embodiment, each cell can define either a code for padding or acode for paging transmission cell identification as a code which thecell transmits when not transmitting any paging signal at the initialsetting time. Only when receiving a notification of paging occurrencewhich accompanies a paging request from an MME, an MCE, or an MBMS-GW,each cell can transmit either the code for padding or the code forpaging transmission cell identification, as a code with which the celltransmits a paging signal, only to a mobile terminal to which is adestination of this notification. Using this configuration, because itbecomes unnecessary to transmit a notification that paging has notoccurred from the MME, the MCE, or the MBMS-GW to each cell, the amountof signaling can be reduced.

As a concrete example of the configuration of disposing both a cellwhich transmits a paging signal, and a cell which does not transmit anypaging signal, the method of transmitting a code for padding from thecell which does not transmit any paging signal is disclosed. In a casein which the physical area onto which a paging signal is mapped isdetermined, the transmission power required for transmission of thisphysical area from the cell which does not transmit any paging signalcan be set to 0. Nothing can be transmitted via this physical area.Because the physical area onto which a paging signal is mapped isdetermined in the base station in the cell which does not transmit anypaging signal, the transmission power of the above-mentioned physicalarea can be reduced. The transmission power can be set to 0, or nothingcan be transmitted. Therefore, in a cell which does not transmit anypaging signal, a paging signal does not have to be a code for paddingand can be any code. As a result, the interference which occurs whendifferent signals are transmitted between cells each of which carriesout MC transmission in an MBSFN area or an MBSFN synchronization area,i.e., the interference to the cell which transmits a paging signal fromanother cell which does not transmit any paging signal can beeliminated. Furthermore, in a cell which does not transmit any pagingsignal, the base station can increase the power required fortransmission of another physical area by a reduction down to zero in thepower required for transmission of the above-mentioned physical area.Furthermore, in a cell which does not transmit any paging signal, thebase station can achieve a reduction in its low power consumptionbecause the base station reduces the power required for transmission ofthe above-mentioned physical area to zero. The physical area onto whichall of a paging signal is mapped does not have to be determined. Forexample, this method can be applied to a case in which the physical areaonto which a part of a paging signal (e.g., information showing thepresence or absence of paging) is mapped is determined. Furthermore,this method can also be applied to a case in which the physical areaonto which a paging signal presence or absence indicator disclosed inEmbodiment 7 or 9 is mapped is determined.

Using the configuration as mentioned in this embodiment, it becomes ableto dispose both a cell which transmits a paging signal and a cell whichdoes not transmit any paging signal, and, even in a case in which eitheran MBSFN area or an MBSFN synchronization area is a huge areageographically, it becomes able to limit the cells each of whichtransmits a paging signal to a mobile terminal to a cell in which themobile terminal is being located, and neighboring cells. Even in thecase of limiting the cells each of which transmits a paging signal to amobile terminal to a cell in which the mobile terminal is being located,and neighboring cells, there is provided an advantage of making itpossible for each mobile terminal to receive the paging signal destinedtherefor without causing degradation in the quality of reception of thedesired paging signal due to a different signal transmitted from anothercell which does not transmit any paging signal. Particularly, there isprovided another advantage of making it possible for a mobile terminalbeing located in the vicinity of a boundary between a cell whichtransmits a paging signal and a cell which does not transmit any pagingsignal to receive a high-quality paging signal. In addition, in a caseof, for example, transmitting a paging signal to only cells in one ormore MBSFN areas which are geographically close to the tracking area ofa unicast cell, an MME which has received a paging request does not haveto transmit a paging request signal to all MCEs respectivelycorresponding to all MBSFN areas in the MBSFN synchronization area, andhas only to transmit the paging request signal only to an MCE whichcontrols the above-mentioned one or more MBSFN areas. Therefore, the MCEwhich has received the paging request signal is enabled to transmit thepaging signal to the cells in the MBSFN areas which the MCE controls,while another MCE which has not received the paging request signal isenabled not to transmit any paging signal in the MBSFN areas which theother MCE controls. Therefore, there is provided an advantage of beingable to reduce the amount of signaling between the MME and the MCEs. Inaddition, by limiting the cells each of which transmits a paging signalto a mobile terminal to a cell in which the mobile terminal is beinglocated, and neighboring cells, it becomes able to use the physicalresource used for transmission of a paging signal destined for a mobileterminal for transmission of a paging signal destined for another mobileterminal at a geographically distant location, and therefore theefficiency of the radio resources can be improved.

In above-mentioned Embodiments 1 to 10, the method of transmitting apaging signal via a multi-cell transmission scheme from cells in afrequency layer dedicated to MBMS transmission by carrying the pagingsignal onto an MBSFN subframe is disclosed. Hereafter, a method oftransmitting a paging signal via an MBSFN subframe in a cell in aunicast/MBMS mixed frequency layer will be disclosed. In a cell in aunicast/MBMS mixed frequency layer, an MBSFN subframe is provided inorder to carry out MC transmission. The method disclosed in any ofEmbodiments 1 to 10 is applied to this MBSFN subframe so as to transmita paging signal. As a concrete example, Embodiment 7 can be applied tothe MBSFN subframe, and a paging signal or a paging signal presence orabsence indicator can be mapped onto a PMCH in the MBSFN subframe. As analternative, Embodiment 8 can be applied to the MBSFN subframe, and achannel (DPCH) dedicated to paging can be formed in the MBSFN subframeand a paging signal (a paging message or information for informing thepresence or absence of paging) can be mapped onto this channel dedicatedto paging. As an alternative, Embodiment 9 can be applied to the MBSFNsubframe, and a main PMCH can be provided in an MBSFN subframetransmitted in an MBSFN synchronization area and a paging signal or apaging signal presence or absence indicator can be mapped onto this mainPMCH. Furthermore, in a case in which a paging signal is transmittedonly to some cells in a unicast/MBMS mixed frequency layer in either anMBSFN area or an MBSFN synchronization area, the method shown inEmbodiment 10 can be applied.

As mentioned above, the use of the method of transmitting a pagingsignal by using an MBSFN subframe in a cell in a unicast/MBMS mixedfrequency layer makes it possible to use a PDSCH and an MBSFN subframefor transmission of a paging signal. Therefore, the method of deriving apaging occasion does not have to handle only a subframe in which thePDSCH exists, except subframes which can be MBSFN subframes, andtherefore there can be provided an advantage of making effective use ofthe radio resources, and reducing the delay time occurring in theincoming call process. Mobile terminals being served by a cell in aunicast/MBMS mixed frequency layer include mobile terminals each ofwhich is receiving an MBMS (MBMS-related information, an MCCH, and anMTCH), and mobile terminals each of which is not receiving an MBMS.Because a mobile terminal which is not receiving an MBMS does not haveto receive an MBSFN subframe, a paging signal can be transmitted to thismobile terminal with a subframe in which the PDSCH exists while a pagingsignal can be transmitted to a mobile terminal which is receiving anMBMS with the PDSCH and an MBSFN subframe. As the method of mapping apaging signal onto an MBSFN subframe, the above-mentioned method can beused. Accordingly, each mobile terminal becomes able to receive a pagingsignal with a subframe according to its reception capability.Furthermore, because a mobile terminal which is receiving an MBMSreceives an MBSFN subframe, a paging signal destined for the mobileterminal currently receiving the MBMS can be mapped onto an MBSFNsubframe by using the above-mentioned method. As a result, the mobileterminal currently receiving the MBMS can receive the paging signalwithout waiting for a paging cycle for unicast (a DRX cycle), andtherefore there is provided an advantage of being able to reduce thedelay time occurring before the reception.

A paging signal destined for a mobile terminal which has carried outcounting when carrying out MBMS reception can be mapped onto an MBSFNsubframe. The counting is an operation of transmitting informationshowing that a mobile terminal will receive an MBMS from the mobileterminal to the network side. Because the network side becomes able toacquire information about an identification number (UE-ID or the like)of a mobile terminal which has carried out the counting, the networkside has only to transmit the paging signal destined for the mobileterminal which has carried out the counting by carrying the pagingsignal onto an MBSFN subframe on the basis of this information. Becausethe network side can recognize that the mobile terminal which hascarried out the counting will receive an MBMS, the network sidecertainly becomes able to transmit the paging signal to this mobileterminal with an MBSFN subframe. In a case in which the counting iscarried out for each MBMS service, what is necessary is just to map apaging signal onto an MBSFN subframe via which an MBMS service for whichthe counting has been carried out is transmitted to transmit the pagingsignal.

In a case of carrying a paging signal on the PMCH in an MBSFN subframe,a part of the paging signal can be transmitted by using a symbol forL1/L2 control signal of this MBSFN subframe and the remainder of thepaging signal can be transmitted by using the PMCH of this MBSFNsubframe. As a concrete example, information showing the existence ofthe paging signal is mapped onto the symbol for L1/L2 control signal anda paging message is mapped onto the PMCH, and they are transmitted tothe corresponding mobile terminal. As the information showing theexistence of the paging signal, either a 1-bit information showing thepresence or absence of the paging signal or information about allocationof the paging signal can be used. Scheduling information (pagingoccasion) of the information showing the existence of the paging signalcan be predetermined, or can be transmitted, via a BCCH, from theserving cell. The network side and the mobile terminal side can derivethe scheduling information of the information showing the existence ofthe paging signal by using an identical parameter and an identicalcomputation expression. Using this configuration, the amount ofsignaling between the mobile terminal and the network can be reduced.The information showing the existence of the paging signal can bemultiplied by the identification code specific to the mobile terminalitself. Using this configuration, the mobile terminal can carry outblind detection of the paging signal destined for the mobile terminalitself. Because the mobile terminal can know the presence or absence ofthe paging signal and the area to which the paging signal is allocatedeven if the paging signal presence or absence indicator is not mappedonto the PMCH, the mobile terminal has only to receive this pagingsignal only when the paging signal exists, whereas the mobile terminaldoes not have to perform the operation of receiving the paging signalwhen the paging signal does not exist. Therefore, there is provided anadvantage of being able to achieve low power consumption in the mobileterminal.

When a tracking area for paging in a unicast differs from a trackingarea at the time of multi-cell transmission in an MBMS in a unicast/MBMSmixed frequency layer, there arises a problem that a part of a pagingsignal which is transmitted via a unicast transmission scheme by using asymbol for L1/L2 control signal, and the remaining paging signal whichis transmitted via a multi-cell transmission scheme by using a PMCH arenot transmitted from an identical cell. There occurs a state in whichonly information showing the existence of paging is transmitted from acell included only in a tracking area for unicast transmission whileonly a remaining paging message is transmitted from a cell included onlyin a tracking area for multicast transmission. In order to solve thisproblem, a tracking area for unicast is made to be the same as atracking area for multi-cell transmission in an MBMS. A single trackingarea can be used both for unicast transmission and for multi-celltransmission. As an alternative, there can be provided two trackingareas to each of which the same cells belong. The tracking areas can bemanaged by either an MME or an MCE. As an alternative, the trackingareas can be managed by both of them. Using this configuration, anidentical cell can transmit a part of a paging signal by using a symbolfor L1/L2 control signal and can also transmit the remaining pagingsignal by using a PMCH in the same MBSF subframe. Therefore, because thedecoding of the paging signal becomes simplified in the MME, the MCE,the base station, and each mobile terminal, there is provided anadvantage of reducing the complexity of the paging signal receptioncontrol and speeding up the processing.

Embodiment 11

FIG. 10 is a block diagram showing the whole configuration of a mobilecommunication system in accordance with the present invention. In FIG.10, a mobile terminal 101 carries out transmission and reception ofcontrol data (C-plane) and user data (U-plane) to and from a basestation 102. Base stations 102 are classified into unicast cells 102-1each of which handles only transmission and reception of unicast, mixedcells 102-2 each of which handles transmission and reception of unicastand MBMS services (MTCH and MCCH), and MBMS dedicated cells 102-3 eachof which handles only transmission and reception of MBMS services. Eachof a unicast cell 102-1 handling transmission and reception of unicastand an MBMS/Unicast-mixed cell (a mixed cell) 102-2 handlingtransmission and reception of unicast is connected to an MME 103 via aninterface S1_MME. Each of a unicast cell 102-1 handling transmission andreception of unicast and a mixed cell 102-2 handling transmission andreception of unicast is also connected to an S-GW 104 via an interfaceS1_U for transmission and reception of unicast user data. The MME 103 isconnected to a PDNGW (Packet Data Network Gateway) 902 via an interfaceS11. An MCE 801 allocates radio resources to all base stations 102existing in an MBSFN area in order to carry out multi-cell (MC)transmission. For example, a case in which both an MBSFN area #1consisting of one or more MBMS/Unicast-mixed cells 102-2, and an MBSFNarea #2 consisting of one or more MBMS dedicated cells 102-3 exist willbe considered. An MBMS/Unicast-mixed cell 102-2 is connected to an MCE801-1 that allocates radio resources for all the base stations existingin the MBSFN area #1 via an interface M2. Furthermore, an MBMS dedicatedcell 102-3 is connected to an MCE 801-2 that allocates radio resourcesfor all the base stations existing in the MBSFN area #2 via an interfaceM2.

An MBMS GW 802 can be divided into an MBMS CP 802-1 that handles controldata, and an MBMS UP 802-2 that handles user data. Each of anMBMS/Unicast-mixed cell 102-2 and an MBMS dedicated cell 102-3 isconnected to the MBMS CP 802-1 via an interface M1 for transmission andreception of MBMS-related control data. Each of an MBMS/Unicast-mixedcell 102-2 and an MBMS dedicated cell 102-3 is connected to the MBMS UP802-2 via an interface M1_U for transmission and reception ofMBMS-related user data. The MCE 801 is connected to the MBMS CP 802-1via an interface M3 for transmission and reception of MBMS-relatedcontrol data. The MBMS UP 802-2 is connected to an eBMSC 901 via aninterface SGimb. The MBMS GW 802 is connected to the eBMSC 901 via aninterface SGmb. The eBMSC 901 is connected to a content provider. TheeBMSC 901 is connected to a PDNGW 902 via an interface SGi. The MCE 801is connected to an MME 103 via an interface (IF) between MME and MCEwhich is a new interface.

FIG. 11 is a block diagram showing the configuration of a mobileterminal 101 for use in the system in accordance with the presentinvention. In FIG. 11, a transmitting process of the mobile terminal 101is performed as follows. First, control data from a protocol processingunit 1101 and user data from an application unit 1102 are stored in atransmission data buffer unit 1103. The data stored in the transmissiondata buffer unit 1103 are delivered to an encoder unit 1104, and aresubjected to an encoding process such as an error correction. There canexist data which are outputted directly from the transmission databuffer unit 1103 to a modulating unit 1105 without being encoded. Amodulation process is performed on the data on which the encodingprocess has been performed by the encoder unit 1104 by the modulatingunit 1105. After the modulated data are converted into a basebandsignal, the baseband signal is outputted to a frequency converting unit1106 and is converted into a transmission signal having a radiotransmission frequency by the frequency converting unit 1106. Afterthat, the transmission signal is transmitted to a base station 102 viaan antenna 1107. The mobile terminal 101 also performs a receivingprocess as follows. A radio signal from a base station 102 is receivedby the antenna 1107. The received signal having a radio receptionfrequency is converted into a baseband signal by the frequencyconverting unit 1106, and a demodulation process is performed on thebaseband signal by a demodulating unit 1108. Data which are obtainedthrough the demodulating process are delivered to a decoder unit 1109,and are subjected to a decoding process such as an error correction.Control data included in the decoded data are delivered to the protocolprocessing unit 1101 while user data included in the decoded data aredelivered to the application unit 1102. The series of processes carriedout by the mobile terminal are controlled by a control unit 1110.Therefore, although not shown in the drawing, the control unit 1110 isconnected to each of the units (1101 to 1109).

FIG. 12 is a block diagram showing the configuration of a base station102. The base station 102 performs a transmitting process as follows. AnEPC communication unit 1201 transmits and receives data between the basestation 102 and an EPC (an MME 103 and an S-GW 104). An other basestation communicating unit 1202 transmits and receives data to and fromanother base station. Each of the EPC communication unit 1201 and theother base station communicating unit 1202 carries out reception andtransmission of information from and to a protocol processing unit 1203.Control data from the protocol processing unit 1203, and user data andcontrol data from the EPC communication unit 1201 and the other basestation communicating unit 1202 are stored in a transmission data bufferunit 1204. The data stored in the transmission data buffer unit 1204 aredelivered to an encoder unit 1205, and subjected to an encoding processsuch as an error correction. There can exist data which are outputteddirectly from the transmission data buffer unit 1204 to a modulatingunit 1206 without being encoded. The modulating unit 1206 performs amodulation process on the encoded data. After the modulated data areconverted into a baseband signal, the baseband signal is outputted to afrequency converting unit 1207 and is converted into a transmissionsignal having a radio transmission frequency by the frequency convertingunit 1207. After that, the transmission signal is transmitted from anantenna 1208 to one or more mobile terminals 101. The base station 102also performs a receiving process as follows. A radio signal from one ormore mobile terminals 101 is received by the antenna 1208. The receivedsignal having a radio reception frequency is converted into a basebandsignal by the frequency converting unit 1207, and a demodulation processis performed on the baseband signal by a demodulating unit 1209. Datawhich are obtained through the demodulating process are delivered to adecoder unit 1210, and are subjected to a decoding process such as anerror correction. Control data among the decoded data are delivered tothe protocol processing unit 1203 or the EPC communication unit 1201 andthe other base station communicating unit 1202, and user data among thedecoded data are delivered to the EPC communication unit 1201 and theother base station communicating unit 1202. The series of processescarried out by the base station 102 are controlled by a control unit1211. Therefore, although not shown in the drawing, the control unit1211 is connected to each of the units (1201 to 1210).

FIG. 13 is a block diagram showing the configuration of an MME (MobilityManagement Entity). A PDN GW communication unit 1301 carries outtransmission and reception of data between the MME 103 and a PDN GW 902.A base station communication unit 1302 carries out transmission andreception of data between the MME 103 and a base station 102 via anS1_MME interface. When data received from the PDN GW 902 is user data,the user data is delivered from the PDN GW communication unit 1301 tothe base station communication unit 1302 via a user plane processingunit 1303, and is then transmitted to one or more base stations 102.When data received from a base station 102 is user data, the user datais delivered from the base station communication unit 1302 to the PDN GWcommunication unit 1301 via the user plane processing unit 1303, and isthen transmitted to the PDN GW 902. An MCE communication unit 1304carries out transmission and reception of data between the MME 103 andan MCE 801 via an IF between MME and MCE.

When data received from the PDN GW 902 is control data, the control datais delivered from the PDN GW communication unit 1301 to a control planecontrol unit 1305. When data received from a base station 102 is controldata, the control data is delivered from the base station communicationunit 1302 to the control plane control unit 1305. Control data receivedfrom an MCE 801 is delivered from the MCE communication unit 1304 to thecontrol plane control unit 1305. The results of a process carried out bythe control plane control unit 1305 are transmitted to the PDN GW 902via the PDN GW communication unit 1301, are then transmitted, via anS1_MME interface, to one or more base stations 102 by way of the basestation communication unit 1302, and are then transmitted, via an IFbetween MME and MCE, to one or more MCEs 801 by way of the MCEcommunication unit 1304. A NAS security unit 1305-1, an SAE bearercontrol unit 1305-2, and an idle state (Idle State) mobility managingunit 1305-3 are included in the control plane control unit 1305, and thecontrol plane control unit carries out general processes for controlplane. The NAS security unit 1305-1 carries out security work for a NAS(Non-Access Stratum) message, etc. The SAE bearer control unit 1305-2carries out management of a bearer of SAE (System ArchitectureEvolution), etc. The idle state mobility managing unit 1305-3 carriesout mobility management of an idle state (an LTE-IDLE state, simplyreferred to as idle), generation and control of a paging signal at thetime of an idle state, addition, deletion, update, and retrieval of atracking area (TA) of one or more mobile terminals 101 being served by abase station, management of a tracking area list (TA List), etc. The MMEstarts a paging protocol by transmitting paging messages to cellsbelonging to a tracking area (tracking area: TA) in which UEs areregistered (registered). The series of processes carried out by the MME103 are controlled by a control unit 1306. Therefore, although not shownin the drawing, the control unit 1306 is connected to each of the units(1301 to 1305).

FIG. 14 is a block diagram showing the configuration of an MCE(Multi-cell/multicast Coordination Entity). An MBMS GW communicationunit 1401 carries out transmission and reception of control data betweenthe MCE 801 and an MBMS GW 802 via an M3 interface. A base stationcommunication unit 1402 carries out transmission and reception ofcontrol data between the MCE 801 and a base station 102 via an M2interface. An MME communication unit 1403 carries out transmission andreception of control data between the MCE 801 and an MME 103 via an IFbetween MME and MCE. An MC transmission scheduler unit 1404 carries outscheduling of multi-cell transmission of one or more MBSFN areas whichthe MC transmission scheduler unit manages by using control data fromthe MBMS GW 802 delivered thereto via the MBMS GW communication unit1401, control data from a base station 102 in an MBSFN (MultimediaBroadcast multicast service Single Frequency Network) area, which aredelivered thereto via the base station communication unit 1402, andcontrol data from the MME 103 which are delivered thereto via the MMEcommunication unit 1403. As an example of the scheduling, radioresources (time, frequency, etc.) of a base station, a radioconfiguration (a modulation method, a code, etc.), etc. can be provided.The results of the scheduling of multi-cell transmission are deliveredto the base station communication unit 1402, and are then transmitted toone or more base stations 102 in the MBSFN area. The series of processescarried out by the MCE 801 are controlled by a control unit 1405.Therefore, although not shown in the drawing, the control unit 1405 isconnected to each of the units (1401 to 1404).

FIG. 15 is a block diagram showing the configuration of an MBMS gateway.In FIG. 15, an eBMSC communication unit 1501 of the MBMS GW 802 carriesout transmission and reception of data (user data and control data)between the MBMS GW 802 and an eBMSC 901. The MCE communication unit1502 carries out transmission and reception of control data between theMBMS GW 802 and an MCE 801 via an M3 interface. Control data receivedfrom the eBMSC 901 are delivered to an MBMS CP unit 1503 via the eBMSCcommunication unit 1501, and, after being processed by the MBMS CP unit1503, are transmitted to one or more MCEs 801 via the MCE communicationunit 1502. Control data received from the MCE 801 are delivered to theMBMS CP unit 1503 via the MCE communication unit 1502, and after beingprocessed by the MBMS CP unit 1503, are transmitted to the eBMSC901and/or the MCE 801 via the eBMSC communication unit 1501. Abase stationcommunication unit 1504 transmits user data (also referred to as trafficdata) to the MBMS GW 802 and one or more base stations via an M1_Uinterface. User data received from the eBMSC 901 are delivered to anMBMS UP unit 1505 via the eBMSC communication unit 1501, and, afterbeing processed by the MBMS UP unit 1505, are transmitted to one or morebase stations 102 via the base station communication unit 1504. The MBMSCP unit 1503 and the MBMS UP unit 1505 are connected to each other. Theseries of processes carried out by the MBMS GW 802 is controlled by acontrol unit 1506. Therefore, although not shown in the drawing, thecontrol unit 1506 is connected to each of the units (1501 to 1506).

Next, an example of a flow of processing carried out by the mobilecommunication system in accordance with the present invention will beshown in FIG. 16. FIG. 16 is a flow chart showing an outline ofprocessing including from a process of starting using an MBMS to aprocess of ending the use of the MBMS, which is carried out by a mobileterminal in the communication system which uses an LTE method. Themobile terminal, in step ST1601 of FIG. 16, carries out a cell selectionof a serving cell in an MBMS/Unicast-mixed cell. Hereafter, the processof step 1601 will be referred to as a “unicast side cell selection”. Anetwork side, in step ST1601-1, carries out a process of “broadcastinginformation about a receivable MBMS” to the mobile terminal. Morespecifically, the network side informs the mobile terminal that acurrently-available MBMS service exists, or about information regardingfrequencies of the MBMS service (a list of frequencies). Because throughthe process of ST1601-1, the mobile terminal can know that acurrently-available MBMS service exists, and know the information aboutfrequencies of the MBMS service, the mobile terminal does not have tosearch for a receivable frequency in a round-robin manner. As a result,there is provided an advantage of shortening a control delay timeoccurring before the mobile terminal receives a service at a frequencyother than a currently-selected frequency.

The mobile terminal, in step ST1602, carries out a search process ofsearching for an MBMS transmission dedicated cell on the basis of theinformation transmitted thereto from the network side in step ST1601. Asan example of the search process, there is provided acquisition oftiming synchronization (synchronization with radio frame timing), andsystem information, such as a system bandwidth, the number oftransmission antennas, an MBSFN area identifier (ID) (also referred toas an MBSFN area number), and MCCH (multicast control channel)-relatedinformation, etc. Hereafter, the process of step 1602 will be referredto as a “search for MBMS”. The mobile terminal, in step ST1603, receivesinformation used for receiving an MBMS service (an MCCH and an MTCH) inthe MBMS transmission dedicated cell from the network side. Hereafter,the process of step 1603 will be referred to as “MBMS area informationacquisition”. The user (mobile terminal), in step ST1604, selects anMBMS service which the user desires by using the information used forreceiving the MBMS service received from the network side in stepST1603. Hereafter, the process of step 1604 will be referred to as “MBMSservice selection”.

It has been examined that in a communication system based on an LTEmethod, only a downlink for transmitting broadcast data provided by anMBMS service to mobile terminals is disposed while any uplinks areomitted, and a cell dedicated to MBMS transmission which implements asimple system configuration is disposed. In the above-mentionedexplanation of steps ST1601-1 to ST1604, the method of selecting an MBMSservice using such an MBMS transmission dedicated cell is disclosed.Therefore, there is provided an advantage of enabling the mobileterminal to receive a desired MBMS service by means of the MBMStransmission dedicated cell through the previously-explained series ofprocesses.

The mobile terminal, in step ST1605, makes preparations for carrying outdiscontinuous reception of MBMS data from the MBMS transmissiondedicated cell by using the information used for receiving an MBMSservice received from the network side in step ST1603. Hereafter, theprocess of step 1605 will be referred to as “preparations fordiscontinuous reception at the time of MBMS reception”. The mobileterminal, in step ST1606, carries out an “MBMS side receiving statenotification” process of notifying the state of receiving the MBMS inthe MBMS transmission dedicated cell to the network side. Because theMBMS transmission dedicated cell does not have any uplink disposedtherein, any mobile terminal currently receiving MBMS data in the MBMSdedicated cell cannot carry out location registration into the networkside. In this case, because the network side cannot specify the cell inwhich the mobile terminal is being located, it is difficult for thenetwork side to transmit a paging signal to the mobile terminal when anincoming call destined for the mobile terminal occurs. Because thenetwork side, in this step ST1606, can know that the mobile terminal isreceiving an MBMS service in the MBMS transmission dedicated cell, andbecomes able to keep track of the mobile terminal, when an incoming calldestined for the mobile terminal currently using the MBMS service in theMBMS transmission dedicated cell occurs, the network side can transferpaging information to the MBMS transmission dedicated cell via an MME103 and an MCE 801-1 to notify that a dedicated incoming call destinedfor the mobile terminal currently using the MBMS service is occurring.Therefore, the problem about paging to a mobile terminal currently usingan MBMS service in an MBMS transmission dedicated cell can be solved.

The mobile terminal, in step ST1607, carries out a measurement(measurement) process including a measurement of the electric fieldintensity of a unicast cell (102-1 in FIG. 10) and/or that of anMBMS/Unicast-mixed cell (102-2 in FIG. 10), and a cell selection. Thisprocess will be referred to as a “unicast side measurement”. Byperforming this step ST1607, the mobile terminal which is receiving anMBMS service in the frequency layer dedicated to MBMS transmissionbecomes able to carryout a measurement of a unicast/mixed frequencylayer. As a result, there can be provided an advantage of being able tocarry out management of the mobility of the mobile terminal via theunicast/mixed frequency layer even if the mobile terminal is receivingan MBMS service in the frequency layer dedicated to MBMS transmissioncomprised of an MBMS-dedicated base station for which no uplink exists.The mobile terminal which is receiving an MBMS service in the frequencylayer dedicated to MBMS transmission, in step ST1608, carries outdiscontinuous reception for reception of a paging signal. The networkside transmits a paging signal destined for the mobile terminal which isreceiving an MBMS service in the frequency layer dedicated to MBMStransmission with the discontinuous reception configuration at the timeof MBMS reception. Hereafter, the process of step 1608 will be referredas to the “discontinuous reception at the time of MBMS reception”. Insteps ST1605 to ST1608, the method of transmitting a paging signal, andthe mobile communication system which enables the method to beimplemented therein can be disclosed for a mobile terminal which isreceiving an MBMS service in the frequency layer dedicated to MBMStransmission. As a result, there is provided an advantage of enablingeven a mobile terminal which is receiving an MBMS service in thefrequency layer dedicated to MBMS transmission to receive a pagingsignal. The mobile terminal which has not received the paging signalthrough the “discontinuous reception at the time of MBMS reception” ofstep ST1608 makes a transition to step ST1609.

The mobile terminal, in step ST1609, receives MBMS traffic data (anMTCH) transmitted thereto from the frequency layer dedicated to MBMStransmission. Hereafter, the process of step ST1609 will be referred toas “MTCH reception”. The mobile terminal which is carrying out the “MTCHreception” makes a transition to step ST1607 at the time of the “unicastside measurement”. As an alternative, the mobile terminal which iscarrying out the “MTCH reception” makes a transition to step ST1602 orST1604 when the receive sensitivity becomes worse. The mobile terminalwhich has received the paging signal through the “discontinuousreception at the time of MBMS reception” of step ST1608 makes atransition to step ST1610. The mobile terminal, in step ST1610, movesfrom the frequency layer dedicated to MBMS transmission to theunicast/mixed frequency layer, and carries out transmission andreception of control data to and from either a unicast cell or a mixedcell. Hereafter, the process of step ST1610 will be referred to as the“unicast side discontinuous reception”. As a result, the mobile terminalin question becomes able to transmit uplink data to the network side byusing the unicast/mixed frequency layer. Therefore, the method ofenabling a mobile terminal which has received a paging signal in thefrequency layer dedicated to MBMS transmission for which no uplinkexists to transmit a response to the paging signal in the unicast/mixedfrequency layer, and the mobile communication system which enables themethod to be implemented therein can be disclosed.

The mobile terminal, in steps ST1611, informs the network side that themobile terminal will end the reception of the MBMS in the frequencylayer dedicated to MBMS transmission. Hereafter, the process of stepST1611 will be referred to as the “MBMS reception end notification”. Byperforming this step ST1611, the mobile terminal enables the networkside to know that the mobile terminal in question will end the receptionof the MBMS service in the frequency layer dedicated to MBMStransmission. Therefore, the network side can discontinue theconfiguration of transmitting the paging signal to the mobile terminalin question in the frequency layer dedicated to MBMS transmission. As aresult, the mobile communication system becomes able to stop thetransmission of the paging signal, which the mobile terminal in questionwill not receive, to the mobile terminal in question from the frequencylayer dedicated to MBMS transmission. Therefore, there is provided anadvantage of making effective use of the radio resources.

Hereafter, a detailed concrete example of a flow of the processingcarried out by the mobile communication system, which is described withreference to FIG. 16, will be explained with reference to FIG. 17. FIG.17 is a flow chart explaining a cell selection on a side of unicast.Each of a unicast cell and an MBMS/Unicast-mixed cell (simply refers toa mixed cell (Mixed cell)), in step ST1701, broadcasts a primarysynchronization channel (Primary Synchronization Channel: P-SCH) and asecondary synchronization channel (Secondary Synchronization Channel:S-SCH), and a reference signal (also referred to as a reference symbol,Reference Symbol: RS) to mobile terminals being served thereby. Each ofthe mobile terminals, in step ST1702, receives the P-SCH, the S-SCH, andthe RS from the base station (the unicast cell or/and the mixed cell).Each of the mobile terminals, in step ST1703, carries out an initialcell searching operation by using the P-SCH, the S-SCH, and the RSreceived thereby. The details of the cell searching operation which havebeen being debated in the 3GPP will be explained. In a first step, eachof the mobile terminals carries out blind detection of the primarysynchronization channel (P-SCH) for which three types of specificationsequences exist in the mobile communication system. The P-SCH is mappedonto central 72 subcarriers of the system bandwidth in frequency, and ismapped onto the 1st (#0) and 6th (#5) subframes of each radio frame intime. Therefore, each of the mobile terminals which has blind-detectedthe P-SCH can detect 5 ms-timing and know cell groups (first to thirdgroups corresponding to the above-mentioned three types of sequences ofP-SCH). In a second step, each of the mobile terminals carries out blinddetection of the secondary synchronization channel (S-SCH). The mappingpositions of the S-SCH are the same as those of the P-SCH. Each of themobile terminals which has blind-detected the S-SCH can detect 10ms-timing (frame synchronization) and the cell identifier (Cell ID).

Each of the mobile terminals, in step ST1704, carries out a cellselection. The cell selection is a process of selecting one base stationwhich satisfies the requirements for becoming a serving base station(cell) by using the results of a measurement of the downlink receivesensitivity of each of a plurality of base stations, which is carriedout by each of the mobile terminals. As an example of the requirementsfor becoming a serving base station, there can be considered a case inwhich the base station to be selected has the best one of the downlinkreceive sensitivities of the plurality of base stations, or a case inwhich the base station to be selected has a receive sensitivityexceeding a minimum threshold of the receive sensitivity of a servingbase station. As a value which each of the mobile terminals actuallymeasures, there is reference symbol received power (Reference Symbolreceived power: RSRP), or an E-UTRA carrier received signal strengthindicator (E-UTRA carrier received signal strength indicator: RSSI). Aserving base station is a base station which takes charge of schedulingof the mobile terminal in question. Even abase station other than theserving base station for the mobile terminal in question can become aserving base station for other mobile terminals. That is, each of allbase stations each of which is a unicast cell or an MBMS/Unicast-mixedcell has a scheduling function, and can become a serving base stationfor some mobile terminals. Each of the unicast cell and theMBMS/Unicast-mixed cell, in step ST1705, transmits broadcast informationby using a broadcast control channel (BCCH) which is one of the logicalchannels. The broadcast information includes, as an example, ameasurement period length, a discontinuous reception cycle length, andtracking area information (TA information). The measurement periodlength is informed from the network side to the mobile terminals beingserved thereby, and each of the mobile terminals measures a fieldintensity and so on at periods (cycles) of this period length. Thediscontinuous reception cycle length is the length of each of periods atwhich each of the mobile terminals monitors a paging signal periodicallyin order to receive a paging signal in an idle state (Idle State). TheTA information is the information about a “tracking area” (TrackingArea). By sending a paging message to each eNB belonging to the trackingarea in which UEs are registered, an MME starts a paging process (seeTS36.300 19.2.2.1). Each of the mobile terminals, in step ST1706,receives the measurement period length, the discontinuous receptioncycle length, the TA information, etc., via the BCCH, from the servingbase station.

Each of the unicast cell and the MBMS/Unicast-mixed cell, in stepST1707, broadcasts one or more frequencies of an available MBMS service,i.e., one or more frequencies of a receivable MBSFN synchronization area(MBSFN Synchronization Area) (referred to as one or more frequenciesf(MBMS) s) to the mobile terminals by using the BCCH. In a W-CDMAcommunication system, a parameter called preferred frequency information(Preferred frequency information: PL information) exists. The PLinformation is mapped onto a multicast control channel (MCCH), which isa logical channel, in the network side, and is broadcasted to the mobileterminals being served by the network side. A problem is, however, thatin an LTE system, a unicast cell which does not provide any MBMS serviceis planned to be disposed, and this unicast cell cannot use the methodof broadcasting a frequency f(MBMS) by using the MCCH which is a channelfor MBMS.

Each of the mobile terminals, in step ST1708, receives the frequencyf(MBMS) transmitted thereto by using the BCCH from the serving basestation. By receiving the frequency f(MBMS), each of the mobileterminals does not have to search for a frequency at which a service canbe provided therefor, other than a currently-selected frequency, in around-robin manner. As a result, there is provided an advantage ofshortening a control delay time occurring before the mobile terminalreceives a service at a frequency other than a currently-selectedfrequency. Steps ST1707 and ST1708 are a detailed example of the“broadcasting information about a receivable MBMS” described inEmbodiment 11. In this case, if each f(MBMS) is determined statically(Static) or semi-statically (Semi-Static) in the mobile communicationsystem, there can be provided an advantage of shortening the controldelay time occurring before each of the above-mentioned mobile terminalsreceives a service at a frequency other than the currently-selectedfrequency without broadcasting each frequency f(MBMS) from the basestation. In addition, because it becomes unnecessary to broadcast eachfrequency f(MBMS), an advantage of making effective use of the radioresources can also be provided.

As an alternative, the base station, in steps ST1707 and ST1708, canalso broadcast the system bandwidth and the number of transmissionantennas in each f(MBMS) by using the BCCH in addition to each frequencyf(MBMS). As a result, each of the mobile terminals does not have toacquire the system information (the system bandwidth and the number oftransmission antennas) in the frequency layer dedicated to MBMStransmission by receiving each frequency f(MBMS) transmitted by usingthe BCCH from the serving base station, in step ST1708. Therefore, therecan be provided an advantage of shortening the control delay time. Thisis because even if the amount of information (the system bandwidth andthe number of transmission antennas) increases, the length of processingtime required for each of the mobile terminals to perform the processingdoes not increase so much because each of the mobile terminals needs toreceive the BCCH from the serving base station in the unicast/frequencylayer in order to receive each frequency f(MBMS), while because each ofthe mobile terminals needs to receive the information in the frequencylayer dedicated to MBMS transmission in order to acquire the systeminformation of the frequency layer dedicated to MBMS transmission afterswitching to the frequency layer dedicated to MBMS transmission, andeach of the mobile terminals therefore requires a decoding process ofdecoding another channel newly, a control delay time occurs.

Each of the mobile terminals, in step ST1709, checks to see whether ornot the TA information of the serving base station received in stepST1706 is included in the current tracking area list (TA List) whicheach of the mobile terminals stores in the protocol processing unit 1101or the control unit 1110 thereof. When the TA information is included inthe current tracking area list, each of the mobile terminals makes atransition to step ST1720 of FIG. 18. When the TA information is notincluded in the current tracking area list, each of the mobile terminalsperforms step ST1710. Each of the mobile terminals, in step ST1710,transmits an “attach request” (Attach Request) to the serving basestation to inform that the TA information is not included in the currenttracking area list. As information included in the “attach request”,there are an identifier (IMSI (International Mobile SubscriberIdentity)) or S-TMSI (S-Temporary Mobile Subscriber Identity, S-TMSI maybe simply referred to as Temporary Mobile Subscriber Identity (TMSI)) ofeach of the mobile terminals, and the capability (Capability) of each ofthe mobile terminals. The serving base station which has received the“attach request” in step ST1711, in step ST1712, transmits the “attachrequest” to an MME (Mobility Management Entity) or an HSS (HomeSubscriber Server). The MME, in step ST1713, receives the “attachrequest”. The idle state mobility managing unit 1305-3 of the MMEmanages the tracking area list of each of the mobile terminals. The MME,in step ST1714, checks whether or not the serving base station of themobile terminal in question is included in the tracking area list whichis managed by the mobile terminal in question. When the serving basestation of the mobile terminal in question is included in the trackingarea list, the MME makes a transition to step ST1716 of FIG. 18. Whenthe serving base station of the mobile terminal in question is notincluded in the tracking area list, the MME performs step ST1715. Theidle state mobility managing unit 1305-3 of the MME, in step 1715,carries out a process of adding the TA information of the serving basestation of the mobile terminal in question to the tracking area listwhich is managed by the mobile terminal in question (or updating thetracking area list). The MME, in step ST1716, informs an “attach accept”(Attach Accept) to the serving base station. The “attach accept”includes information such as the tracking area list, and an identifier(S-TMSI or the like) which is provided to the mobile terminal. Theserving base station which, in step ST1717, has received the “attachaccept”, in step ST1718, informs the “attach accept” to the mobileterminal in question. The mobile terminal, in step ST1719, receives the“attach accept”.

FIG. 18 is a flow chart showing an MBMS search process. Steps 1720 to1725 of FIG. 18 are a concrete example of the “search for MBMS”described in Embodiment 11. Each of the mobile terminals, in stepST1720, checks to see whether it has received an frequency of areceivable MBSFN synchronization area (or a frequency of the frequencylayer dedicated to MBMS transmission) in step ST1708. That is, each ofthe mobile terminals checks to see whether it has received one or morefrequencies f(MBMS)s. When there exists no frequency, each of the mobileterminals ends the process. When there exists one or more frequencies,each of the mobile terminals performs step ST1721. Each of the mobileterminals, in step ST1721, checks to see whether the user has anintention of receiving an MBMS service at f(MBMS). As an example of thechecking, when the user has an intention of receiving an MBMS service atf(MBMS), he or she uses a user interface to send a command to each ofthe mobile terminals, and each of the mobile terminals storesinformation showing the user's intention in the protocol processing unit1101. Each of the mobile terminals, in step ST1721, checks to seewhether or not the information showing the user's intention of receivingan MBMS service is stored in the protocol processing unit 1101. When theinformation showing the user's intention of receiving an MBMS service isnot stored, each of the mobile terminals repeats the process of stepST1721. As a method of repeating the process, each of the mobileterminals uses a method of carrying out the determination of step ST1721at constant periods (cycles), or a method of carrying out step ST1721 orST1720 when receiving a notification showing a change in the user'sintention of receiving an MBMS service from the user by way of the userinterface. In contrast, when the information showing the user'sintention of receiving an MBMS service is stored, each of the mobileterminals makes a transition to step ST1722. Each of the mobileterminals, in step ST1722, changes the frequency set to the frequencyconverting unit 1107 (synthesizer) thereof and changes its centerfrequency to f(MBMS) to start the searching operation of searching foran MBMS. Changing the frequency set to the frequency converting unit1107 to change its center frequency is referred to as re-tune (re-tune).The MBMS dedicated cell, in step ST1723, broadcasts a primarysynchronization channel (Primary Synchronization Signal: P-SCH) and asecondary synchronization channel (Secondary Synchronization Signal:S-SCH), a reference signal (RS (MBMS)), and a BCCH to the mobileterminals being served thereby. Each of the mobile terminals, in stepST1724, receives the P-SCH, the S-SCH, the RS (MBMS), and the BCCH(broadcast control channel) from the MBMS dedicated cell.

Each of the mobile terminals, in step ST1725, performs the searchingoperation of searching for an MBMS. The searching operation in thefrequency layer dedicated to MBMS transmission which has been debated inthe 3GPP will be explained. A sequence exclusively used in the frequencylayer dedicated to MBMS transmission is added to the P-SCH. It isassumed that the additional sequence for exclusive use is definedstatically. In a first step, each of the mobile terminals carries outblind detection of the P-SCH in the additional sequence for exclusiveuse. The P-SCH is mapped onto central 72 subcarriers of the systembandwidth in frequency, and is mapped onto the 1st (#0) and 6th (#5)subframes of each radio frame in time. Therefore, each of the mobileterminals which has blind-detected the P-SCH can carry out 5 ms-timingdetection. Furthermore, the P-SCH is transmitted via a multi-celltransmission scheme. In a second step, each of the mobile terminalscarries out blind detection of the S-SCH. The mapping positions of theS-SCH are the same as those of the P-SCH. Each of the mobile terminalswhich has blind-detected the S-SCH can detect 10 ms-timing (framesynchronization) and know the MBSFN area ID. Furthermore, the S-SCH istransmitted via a multi-cell transmission scheme. Each of the mobileterminals receives the BCCH by using the scrambling code (ScramblingCode) related to the MBSFN area ID acquired in the second step. Each ofthe mobile terminals can acquire the scheduling of the MCCH (multicastcontrol channel) by decoding the BCCH. In this decoding process, each ofthe mobile terminals uses the scrambling code (Scrambling Code) relatedto the above-mentioned MBSFN area ID. Furthermore, the BCCH istransmitted via a multi-cell transmission scheme. In the presentinvention, it is assumed that each of the mobile terminals can acquirethe system bandwidth at f(MBMS) and the number of transmission antennasat f(MBMS) by further decoding the BCCH. In a case in which in themobile communication system, the system bandwidth and the number oftransmission antennas at f(MBMS) are determined statically (Static) orsemi-statically (Semi-Static), there can be provided an advantage ofbeing able to eliminate the necessity to broadcast the system bandwidthand/or the number of transmission antennas at f(MBMS) from a basestation to make effective use of the radio resources. Furthermore,because the necessity to change the decoding and the parameters (thesystem bandwidth and/or the number of transmission antennas at f(MBMS))can be eliminated, there can be provided an advantage of achieving lowpower consumption in each mobile terminal, and a reduction of thecontrol delay time.

In the present invention, the scheduling of the MCCH, which is carriedout in step ST1725, will be further studied. According to the currentstandards of the 3GPP, it is defined that an MBSFN synchronization area(Multimedia Broadcast multicast service Single Frequency NetworkSynchronization Area f(MBMS)) can support one or more MBSFN areas (MBSFNAreas) (refer to FIG. 7). In contrast, it has not been decided how tomultiplex a plurality of MBSFN areas with f(MBMS) which is a singlefrequency (Single Frequency). Hereafter, the “MBMS search” process inaccordance with the present invention which is adapted in such a way asto support several different methods of multiplexing MBSFN areas will beexplained in the case of using each of the different multiplexingmethods.

The configuration of a PMCH provided for each MBSFN area is shown inFIG. 60. In the example of FIG. 60, time division multiplexing (TDM) ofMBSFN areas is carried out. A cell #n1 (or a cell #n2 or a cell #n3) isa one included in an MBSFN area 1 (or an MBSFN area 2 or an MBSFN area3). In the current 3GPP, a debate about allocation of MBSFN subframes ina mixed cell has been made as shown in nonpatent reference 2. However,because no subframe for unicast exists in an MBMS dedicated cell, allsubframes are MBSFN subframes. Therefore, the debate made in nonpatentreference 2 cannot be applied just as it is. However, it is important tounify the configuration of a mixed cell and that of an MBMS dedicatedcell as much as possible from the viewpoint of preventing the mobilecommunication system from becoming complicated. To this end, a method ofcarrying out scheduling in an MBMS dedicated cell following the conceptabout the “MBSFN frame cluster” (MBSFN frame Cluster) disclosed bynonpatent reference 2 will be disclosed hereafter. In addition, thepresent invention differs from nonpatent reference 2 in that the presentinvention discloses the scheduling of the MCCH in an MBSFN subframewhich is not touched by nonpatent reference 2. An example of thescheduling of the MCCH has not been discussed in nonpatent reference 2.In the present invention, an example of the scheduling of the MCCH willbe shown.

Because the cell #n1 belongs to the MBSFN area 1, the PMCH correspondingto the MBSFN area is transmitted at a time. The PMCH is transmitted onan MBSFN subframe because the PMCH is transmitted via a multi-celltransmission scheme in each MBSFN area. A set of MBSFN frames to whichthe MBSFN subframes are allocated is referred to as an “MBSFN framecluster” (MBSFN frame cluster). In the MBMS dedicated cell, allsubframes in an MBSFN frame can be the MBSFN subframes used formulti-cell transmission. The length of each of the repetition periods atwhich the MBSFN frame cluster is repeated is expressed as the “MBSFNframe cluster repetition period” (MBSFN frame cluster Repetitionperiod). An MCH which is a transport channel for one or more MBMSservices is mapped onto the PMCH, and either or both of the MCCH whichis a logical channel for MBMS control information and the MTCH which isa logical channel for MBMS data are mapped onto the MCH. The MCCH andthe MTCH can be divided in time and mapped onto the PMCH, and can befurther divided in time and mapped onto a physical area which istransmitted via a multi-cell transmission scheme. For example, the MCCHand the MTCH can be mapped onto different MBSFN subframes which are thephysical area onto which they are mapped. The MCCH can be mapped ontoeach MBSFN frame cluster, or only the MTCH can be mapped onto each MBSFNframe cluster. In a case in which only the MTCH exists, the repetitionperiod of the MCCH differs from the repetition period of the MBSFN framecluster. Furthermore, there is a case in which a plurality of MCCHs aremapped onto each MBSFN frame cluster.

In FIG. 60, the cell #n1 (or the cell #n2 or #n3) belongs to the MBSFNarea 1 (or the MBSFN area 2 or 3), and the PMCH corresponding to eachMBSFN area is transmitted at a time. MCCH1 (or MCCH2 or MCCH3) is MBMScontrol information for the MBSFN area 1 (or the MBSFN area 2 or 3), andMTCH1 (or MTCH2 or MTCH3) is MBMS data for the MBSFN area 1 (or theMBSFN area 2 or 3). The repetition period of the MCCH can differ foreach MBSFN area. In the figure, the MCCH repetition period of the cell#n1 (or the cell #n2) is expressed as the “MCCH Repetition period 1 (or2)”. Time division multiplexing of the PMCHs of the MBSFN areas iscarried out. Therefore, the orthogonality among the cells of the MBSFNareas is acquired in the MBSFN synchronization area in which thesynchronization among the cells is ensured, and the interference from acell in another MBSFN area can be prevented. Because the PMCH istransmitted via a multi-cell transmission scheme in each MBSFN area,each cell in each MBSFN area transmits the same data by using the samePMCH. Because, even if a plurality of MBSFN areas exist overlappedly inone cell, the above-mentioned PMCH configuration can be applied with theorthogonality among the MBSFN areas being maintained.

The details of the scheduling of the MCCH will be explained. A case inwhich an MBSFN frame cluster is shorter than the MCCH repetition periodlength will be explained. A case in which an MBSFN frame cluster islonger than the MCCH repetition period length will be explained below.Hereafter, it will be considered that a starting point value of a timeat which the MCCH is mapped and the MCCH repetition period length areinformed as the scheduling of the MCCH. More concretely, an SFN (SystemFrame Number) is used for the indication of the starting point value. Aconcrete computation expression for calculating the MCCH starting pointvalue is given as follows.The MCCH starting point value=(the SFN number of the leading one ofsystem frames onto which the MCCH is mapped)mod(the MCCH RepetitionPeriod length)

In FIG. 60, the MCCH starting point value 1 of the MBSFN area 1 is 1 mod18=1, 19 mod 8=1, or . . . , and the parameters of the MCCH schedulingof the MBSFN area 1 are the MCCH repetition period length 1 of “18” andthe starting point value 1 of “1”. The MCCH starting point value 2 ofthe MBSFN area 2 is 4 mod 9=4, 13 mod 9=4, 22 mod 9=4, or . . . , andthe parameters of the MCCH scheduling of the MBSFN area 2 are the MCCHrepetition period length 2 of “9” and the starting point value 2 of “4”.As to the MBSFN area 3, the same parameters are provided. The systemframe number SFN at this time is broadcast for each subframe if mappedonto the BCCH, and is effective also when receiving the MCCH from theMCCH starting point value. Furthermore, in a case in which the MCCH ismapped onto some subframes in a radio frame, the SFN, the subframenumbers, etc. can be informed as the starting point.

That is, data which are transmitted from each base station (cell)belonging to the MBSFN area 1 are provided as follows. The P-SCH whichis the sequence exclusively used for the frequency layer dedicated toMBMS transmission, the S-SCH1 onto which the MBSFN area ID1 and so onare mapped, a BCCH1 onto which the MCCH starting point value 1 of “1”,the MCCH repetition period length 1 of “18”, and so on are mapped, andwhich is multiplied by the scrambling code 1 (Scrambling code 1), and anMCCH1 and an MTCH1 of the MBSFN area 1 are transmitted. The resources ofan MCCH2 or 3 and an MTCH2 or 3 from each base station belonging to theMBSFN area 2 or 3 are in a discontinuous transmission (DTX:Discontinuous transmission) state. Each of the MCCH1 and the MTCH2 canbe multiplied by the scrambling code 1. By multiplying each of the MCCH1and the MTCH1 by the scrambling code, there can be provided an advantageof unifying a process to be performed on MBSFN-area-specific data (BCCH,MCCH, and MTCH). In contrast, because the MCCHs and the MTCHs of theareas are subjected to time division multiplexing (TDM), it is notnecessary to multiply each of the MCCH and the MTCH by theMBSFN-area-specific scrambling code. In the case of not multiplying eachof the MCCH1 and the MTCH1 by the scrambling code, there can be providedan advantage of reducing the load of encoding processing on each basestation side and the load of decoding process on each mobile terminalside, and hence reducing the delay time occurring before data reception.

Like in the case of the MBSFN area 1, data which are transmitted fromeach base station belonging to the MBSFN area 2 are provided as follows.The P-SCH which is the sequence exclusively used for the frequency layerdedicated to MBMS transmission, the S-SCH2 onto which the MBSFN area ID2and so on are mapped, a BCCH2 onto which the MCCH starting point value 2of “4”, the MCCH repetition period length 2 of “9”, and so on aremapped, and which is multiplied by the scrambling code 2, and the MCCH2and the MTCH2 of each base station belonging to the MBSFN area 2 aretransmitted. The MCCH1 or 3 and the MTCH1 or 3 from each base stationbelonging to the MBSFN area 1 or 3 are in a discontinuous transmission(DTX: Discontinuous transmission) state. The same goes for the MBSFNarea 3. For the sake of simplicity, the example in which time divisionmultiplexing of the MCCH and the MTCH is carried out for each subframeis shown in FIG. 60. However, the present invention can be applied to acase in which another method of multiplexing the MCCH and the MTCH isused, and a case in which the time division multiplexing is carried outfor each of units other than each subframe. Furthermore, as long as theMCCH repetition period length is determined statically (Static) orsemi-statically (Semi-Static) in the mobile communication system, eachbase station does not have to broadcast the MCCH repetition periodlength. Therefore, because the amount of information to be broadcastdecreases, there can be provided an advantage of making effective use ofthe radio resources.

The configuration of the PMCH provided for each MBSFN area is shown inFIG. 61. In FIG. 61, code division multiplexing (Code DivisionMultiplex) of the PMCHs of each MBSFN area is carried out. The cell #n1(or the cell #n2 or #n3) is a one included in the MBSFN area 1 (or theMBSFN area 2 or 3). In the cell #n1, the PMCH corresponding to the MBSFNarea 1 is transmitted. In this case, this PMCH can be continuous ordiscontinuous in time. In a case in which the PMCH is discontinuous intime, the length of the MBSFN frame cluster repetition period (MBSFNframe cluster Repetition period) becomes equal to the length of each ofthe repetition periods at which an MBSFN frame cluster via which thePMCH corresponding to the MBSFN area is transmitted is repeated. Incontrast, in a case in which the PMCH is continuous in time, the MBSFNframe cluster repetition period can be expressed as 0. As analternative, it is not necessary to inform the MBSFN frame clusterrepetition period explicitly in the case in which the PMCH is continuousin time. The MCCH and the MTCH can be divided in time and mapped ontothe PMCH, and can be further divided in time and mapped onto a physicalarea which is transmitted via a multi-cell transmission scheme. Forexample, the MCCH and the MTCH can be mapped onto different MBSFNsubframes which are the physical area onto which they are mapped as aresult. The length of each of the repetition periods at which the MCCHis repeated is expressed as the MCCH repetition period 1.

Similarly, the PMCH corresponding to the MBSFN area 2 (or the MBSFN area3) is transmitted in the cell #n2 (or the cell #n3). The repetitionperiod of the MCCH can differ in each of the MBSFN areas. The length ofeach of the repetition periods at which the MCCH of the cell #n2 (or thecell #n3) is repeated is expressed as the MCCH repetition period 2 (orthe MCCH repetition period 3). Because data which is multiplied by theMBSFN-area-specific scrambling code is mapped onto the PMCH in each ofthe MBSFN areas, the interference among the MBSFN areas in the MBSFNsynchronization area in which the synchronization among the cells isensured can be suppressed. Because the multi-cell transmission is usedin each of the MBSFN areas, each cell in each of the MBSFN areastransmits the same data, i.e., the data which is multiplied by theMBSFN-area-specific scrambling code by using the same PMCH. Even in acase in which a plurality of MBSFN areas exist overlappedly in one cell,the above-mentioned PMCH configuration can be applied with theinterference among the MBSFN areas being suppressed.

An explanation about the data (P-SCH, S-SCH, and BCCH) transmitted fromeach MBSFN area will be omitted hereafter because the data are the sameas those explained in the case of time division multiplexing describedpreviously. A concrete example of the scheduling of the MCCH is the sameas that explained in the case of time division multiplexing describedpreviously. In the present invention, it is considered that a cellinforms the “starting point value at the time when the MCCH is mapped”and the “MCCH repetition period length” to terminals in order to usethem for the scheduling of the MCCH. More concretely, an SFN (SystemFrame Number) is used for the indication of an offset value. A concretecomputation expression for calculating the starting point value isexpressed by the following equation. The MCCH starting point value=(theSFN number of the leading one of system frames onto which the MCCH ismapped) mod (the MCCH Repetition Period length)

In FIG. 61, the MCCH starting point value of the MBSFN area 1 is 1 mod9=1, 10 mod 9=1, or . . . , and the parameters of the MCCH scheduling ofthe MBSFN area 1 are the MCCH repetition period length 1 of “9” and thestarting point value 1 of “1”. The MCCH starting point value of theMBSFN area 2 is 4 mod 12=4, 16 mod 12=4, or . . . , and the parametersof the MCCH scheduling of the MBSFN area 1 are the MCCH repetitionperiod length 2 of “12” and the starting point value 2 of “4”. As to theMBSFN area 3, the same parameters are provided. Furthermore, in a casein which the MCCH is mapped onto some subframes in a radio frame, theSFN, the subframe numbers, etc. can be informed as the starting point.

That is, data which are transmitted from each base station (cell)belonging to the MBSFN area 1, e.g., the cell #n1 include the P-SCHwhich is the sequence exclusively used for the frequency layer dedicatedto MBMS transmission, the S-SCH1 onto which the MBSFN area ID1 and so onare mapped, the MCCH starting point value 1 of “1”, and the MCCHrepetition period length 1 of “9”. These data are mapped onto the BCCH1,the MCCH1, and the MTCH1, and are further scrambled with the scramblingcode 1 and are transmitted. The same goes for the MBSFN areas 2 and 3.For the sake of simplicity, the example in which time divisionmultiplexing of the MCCH and the MTCH is carried out for each subframeis shown in FIG. 61. However, the present invention can be applied to acase in which another method of multiplexing the MCCH and the MTCH isused, and a case in which the time division multiplexing is carried outfor each of units other than each subframe. Furthermore, as long as theMCCH repetition period length is determined statically (Static) orsemi-statically (Semi-Static) in the mobile communication system, eachbase station does not have to broadcast the MCCH repetition periodlength. Therefore, because the amount of information to be broadcastdecreases, there can be provided an advantage of making effective use ofthe radio resources. Furthermore, in the case in which code divisionmultiplexing of MBSFN areas is carried out, because a differentrepetition period length can be set up for each of the MBSFN areas,there is provided an advantage of being able to carry out schedulingwith high flexibility for MBMS services as compared with the case inwhich time division multiplexing of MBSFN areas is carried out. Inaddition, because the code division multiplexing is used, even whenreceiving MTCHs and MCCHs from a plurality of MBSFN areas, each mobileterminal can separate them from one another. Therefore, because themobile communication system can transmit MTCHs and MCCHs from the MBSFNareas 1 to 3 simultaneously, there can be provided an advantage ofexpanding the frequency and time radio resources which are allocated toone MBSFN area.

Next, the “MBMS area information acquisition” of step ST1603 of FIG. 16will be explained more concretely with reference to FIGS. 18 and 19 asneeded. It is assumed that the MCCH (multicast control channel) of eachMBSFN area is transmitted via a multi-cell transmission scheme.Therefore, an MCE, in step ST1726 of FIG. 18, transmits informationabout allocation of radio resources for transmitting the contents of theMCCH and the MCCH to base stations in the MBSFN area. EachMBMS-dedicated base station, in step ST1727, receives the informationabout allocation of radio resources for transmitting the contents of theMCCH and the MCCH from the MCE. Each base station, in step ST1728 ofFIG. 19, carries out multi-cell transmission of control information,such as MBMS area information, discontinuous reception (DRX)information, and the parameter for discontinuous reception at the timeof MBMS reception (in a concrete example, the number K of paginggroups), by using the MCCH according to the radio resources allocatedthereto by the MCE. Each of the mobile terminals, in step ST1729,receives the MCCH from each base station in the MBSFN area. Each of themobile terminals uses the scheduling of the MCCH received from thenetwork side in step ST1725 for the reception of the MCCH.

A concrete example of the receiving method will be explained. As atypical example, a case in which time division multiplexing of MBSFNareas is carried out as shown in FIG. 60 will be explained. A case inwhich each of the mobile terminals is located within the cell #1belonging to the MBSFN area 1 will be explained. Each of the mobileterminals decodes the BCCH1 (broadcast control channel) to receive, asthe scheduling parameters of the MCCH1, the starting point value 1 of“1” and the MCCH repetition period (MCCH Repetition Period) length 1 of“7”. Furthermore, if an SFN (System. Frame Number) is mapped onto theBCCH, each of the mobile terminals can know the SFN number by decodingthe BCCH. Each of the mobile terminals can determine the SFN number ontowhich the MCCH is mapped according to the following equation.

SFN=the MCCH repetition period length 1×α+the starting point value 1 (αis a positive integer).

Each of the mobile terminals can receive the MCCH1 by receiving anddecoding the radio resources of the SFN number onto which the MCCH1 ismapped. Control information for MBMS service which is transmitted via amulti-cell transmission scheme from the MBSFN area 1 is mapped onto theMCCH1. As a concrete example of the control information, there are MBMSarea information, DRX information, a parameter for discontinuousreception at the time of MBMS reception, etc.

In addition, an example of the MBMS area information will be explainedwith reference to FIG. 60. As the MBMS area information, there can beconsidered the frame structure of each area (the structure of an MBSFNframe cluster (MBSFN frame Cluster) and an MBSFN subframe), contents ofservices, modulation information about the MTCH, etc. As the MBSFN framecluster 1, the number of frames included in a set of frames allocated tothe MBSFN area 1 during one MBSFN frame cluster repetition period isinformed. As the MBSFN subframe 1, the number of a subframe onto whichMBMS data (MTCH and/or MCCH data) are actually mapped in one radio framewithin the MBSFN frame cluster 1 is informed. In a case of offering anMBMS service using an MBMS-dedicated base station, it is not necessaryto share radio resources with unicast data, unlike in a case of using anMBMS/Unicast-mixed cell. Therefore, MBMS data can be mapped onto all thesubframes in one radio frame (however, except portions onto which aP-SCH, an S-SCH, or a BCCH is mapped). In a case of mapping MBMS dataonto all the subframes, it is not necessary to inform the parameterabout MBSFN subframes from the network side to the mobile terminal side.As a result, effective use of the radio resources can be made. As analternative, because by using a method of statically mapping MBMS dataonto all the subframes at the time of transmission of MBMS data from anMBMS dedicated cell in the radio communication system, it becomes ableto transmit large-volume MBMS data and it becomes unnecessary to alsoinform the parameter about MBSFN subframes, effective use of the radioresources can be made. As the contents of services, the contents of MBMSservices being ongoing in the MBMS area 1 are informed. When a pluralityof MBMS services (a movie, sports live broadcasting, etc.) are ongoingin the MBSFN area 1, the contents of the plurality of MBMS services andparameter for multiplexing about these services are informed.

FIG. 62 is an explanatory drawing showing a relationship between a DRXperiod during which transmission of MBMS data to a mobile terminal isdiscontinued and the mobile terminal does not perform its receivingoperation of receiving the MBMS data, and a DRX cycle which is a cyclein which the DRX period is repeated. In addition, an example of the DRX(Discontinuous reception) information will be explained with referenceto FIG. 62. As a solution for enabling the management of mobility ofmobile terminals even in an MBMS transmission dedicated frequency layerwhich consists of base stations dedicated to MBMS, which is a challengeof the present invention, a measurement of a unicast/mixed frequencylayer which is carried out even if a mobile terminal is receiving anMBMS service in a frequency layer dedicated to MBMS transmission will bedisclosed. As a result, there can be provided an advantage of becomingable to ensure the mobility in the MBMS dedicated cells in which nouplink exists via the unicast/mixed cell. Therefore, even a mobileterminal currently receiving an MBMS service in an MBMS transmissiondedicated cell needs to carry out a measurement of a unicast cell and anMBMS/Unicast-mixed cell at constant periods (or cycles). According to aconventional method (3GPP W-CDMA), the length of measurement cycle is anintegral multiple of the length of a discontinuous reception cycle, andis informed from the network side to each mobile terminal by way of anupper layer.

A problem is therefore that, assuming that a mobile terminal currentlyreceiving an MBMS service in an MBMS transmission dedicated cell carriesout a measurement of an unicast cell and an MBMS/Unicast-mixed cell atmeasurement periods (or cycles) of the length informed from an upperlayer by using the conventional method, because a base station whichconstructs an MBSFN synchronization area of a frequency layer dedicatedto MBMS transmission and a base station which constructs a unicast/mixedfrequency layer are asynchronous to each other (asynchronous), themobile terminal has to interrupt the MBMS reception in order to carryout the measurement.

Therefore, in accordance with the present invention, as a solution ofthe above-mentioned problem, one DRX period is provided in the MBSFNsynchronization area (refer to FIG. 62). A DRX period means a timeperiod during which transmission of MBMS data about the MBMS services ofall the MBSFN areas in the MBSFN synchronization area from the networkside to each mobile terminal is discontinued and is not carried out,i.e., a time period during which reception of MBMS data is not carriedout when viewed from the mobile terminal side. Therefore, a mobileterminal currently using an MBMS service in a frequency layer dedicatedto MBMS transmission has an advantage of eliminating the necessity tointerrupt the use of the MBMS service by carrying out a measurement of aunicast cell and an MBMS/Unicast-mixed cell during a DRX period duringwhich no MBMS data are transmitted from the network side. Furthermore,by disposing a DRX period in the MBSFN synchronization area, each mobileterminal is enabled to simultaneously receive MBMS data from MBSFN areasin the MBSFN synchronization area without adding any control operation.

Next, the DRX cycle as shown in FIG. 62 will be explained. The DRX cyclemeans a cycle in which the DRX period explained previously is repeated.According to a conventional method, a measurement period length is set(informed) to each mobile terminal by the network side. In a case inwhich this conventional method is applied also to LTE, if a mobileterminal currently receiving an MBMS service in a frequency layerdedicated to MBMS transmission carries out a measurement in aunicast/mixed frequency layer during the DRX period, the mobile terminalneeds to send information about the DRX cycle length and the DRX periodlength in the frequency layer dedicated to MBMS transmission, via one ofroutes, to a control device (a base station, an MME, a PDNGW, or thelike) on a side of a unicast cell or an MBMS/Unicast-mixed cell.Furthermore, because base stations which construct the unicast/mixedfrequency layer are configured in such a way as to be fundamentallyasynchronous to one another, there is a necessity to inform both the DRXcycle length and the DRX period length in the frequency layer dedicatedto MBMS transmission to each unicast cell or each MBMS/Unicast-mixedcell. This method makes the mobile communication system becomecomplicated, and therefore is not preferred. Therefore, in accordancewith the present invention, the following method will be disclosed.

One or more measurement periods in the unicast/mixed frequency layer aremade to be included in one DRX period in the frequency layer dedicatedto MBMS transmission. As a result, even if any measurement period lengthis informed (set) to each mobile terminal from a unicast cell or anMBMS/Unicast-mixed cell, when each mobile terminal carries out ameasurement of the unicast/mixed frequency layer during the DRX periodwhich is provided in the DRX cycle in the frequency layer dedicated toMBMS transmission, the measurement period length informed from thenetwork side can be satisfied. By using this method, any control deviceof an MBMS transmission dedicated cell (a base station, an MCE, an MBMSgateway, an eBNSC, or the like) does not have to inform the DRX cyclelength and the DRX period length in the MBMS transmission dedicated cellto control devices of a unicast cell and an MBMS/Unicast-mixed cell.Therefore, there is provided an advantage of enabling a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBSFN transmission to carry out a measurement at measurement periods ofa length which a unicast cell or an MBMS/Unicast-mixed cell has informed(set) to the mobile terminal without interrupting the reception of theMBMS service, while preventing the mobile communication system frombecoming complicated, that is, avoiding addition of signaling onto thewireless interface or into the network.

The DRX cycle in the MBMS transmission dedicated cell has a length whichis either a minimum of the measurement period length which can beprovided in a unicast cell and in a unicast/mixed cell, or an integralsubmultiple of the minimum. In a case in which the measurement periodlength which a unicast cell or an MBMS/Unicast-mixed cell can set to amobile terminal currently receiving an MBMS service in the frequencylayer dedicated to MBMS transmission differs from the measurement periodlength which can be provided in the unicast/mixed frequency layer, theDRX cycle has a length which is equal to that of the measurement periodlength which can be set to a mobile terminal currently receiving an MBMSservice in the frequency layer dedicated to MBMS transmission, which isa minimum of the above-mentioned measurement period length, or which isan integral submultiple of the minimum of the above-mentionedmeasurement period length. As a result, even if any measurement periodlength is informed (set) to the mobile terminal from a unicast cell oran MBMS/Unicast-mixed cell, when the mobile terminal carries out ameasurement of the unicast/mixed frequency layer during the DRX periodwhich is provided in the DRX cycle in the frequency layer dedicated toMBMS transmission, the measurement period length informed from thenetwork side can be satisfied. By using this method, any control deviceof an MBMS transmission dedicated cell (a base station, an MCE, an MBMSgateway, an eBNSC, and so on) does not have to inform the DRX cyclelength and the DRX period length in the MBMS transmission dedicated cellto control devices of a unicast cell and an MBMS/Unicast-mixed cell.Therefore, there is provided an advantage of preventing the mobilecommunication system from becoming complicated, that is, avoidingaddition of signaling onto the wireless interface or into the network.Furthermore, the mobile terminal can acquire broadcast information froma serving cell in the unicast/mixed frequency layer during theabove-mentioned DRX period. For example, when the broadcast informationin the serving cell is modified, the mobile terminal can deal with themodification.

A concrete example of the parameters about the DRX information will beexplained with reference to FIG. 62. Concretely, as the parameters aboutthe DRX information, the DRX period length, the DRX cycle length, andthe starting point value (DRX) can be considered. Concretely, the numberof radio frames is used for the indication of each of the DRX periodlength and the DRX cycle length. In FIG. 62, the DRX period length is“4” radio frames (during a period between SFN 4 to SFN 7). Furthermore,the DRX cycle length is “7” radio frames (during a period between SFN 4to SFN 10). In addition, an SFN is used for the indication of thestarting point value (DRX) at which the DRX period starts. Somethingother than the number of radio frames can be used for the indication ofeach of the DRX period length and the DRX cycle length. As a concreteexample, the number of subframes can be used for the indication of eachof the DRX period length and the DRX cycle length. Something other thanan SFN can be used for the indication of the starting point value. As aconcrete example, an offset value from a certain reference value can beused for the indication of the starting point value. In a case in whichthe DRX period corresponds to some subframes in a radio frame, an SFN, asubframe number, and so on can be informed as the starting point. Aconcrete computation expression for calculating the starting point value(DRX) is given by(the starting point value (DRX)=(the SFN number of the leading systemframe at which the DRX period starts)mod(the DRX cycle length).

In FIG. 62, the starting point value (DRX) is 4 mod 7=4, 11 mod 7=4, or. . . . The example in which an SFN is used for the indication of thestarting point value (DRX) is shown above. Furthermore, in the example,one DRX period is provided in the MBSFN synchronization area, aspreviously explained. Therefore, the starting point value (DRX) is alsocommon in base stations in the MBSFN synchronization area. A case inwhich an SFN is used as the starting point value (DRX) will beconsidered. It is assumed that the same number is transmitted from basestations in the MBSFN synchronization area at the same time. In theabove-mentioned example, the DRX information is mapped onto an MCCH andis informed from a base station in an MBSFN area to mobile terminals, aspreviously explained. Similarly, the DRX information can be mapped ontoa BCCH and can be transmitted from a base station in an MBSFN area tomobile terminals. In this case, the same advantages are provided. As analternative, the DRX information can be mapped onto a BCCH and can betransmitted from a serving base station to mobile terminals. In thiscase, the same advantages are provided. Furthermore, even when the DRXinformation is determined statically (Static) or semi-statically(Semi-Static), the same advantages are provided. As a result, because itbecomes unnecessary to broadcast the DRX information, there can also beprovided an advantage of making effective use of the radio resources.

An example of the parameter for discontinuous reception at the time ofMBMS reception will be explained. Nonpatent reference 1 discloses that apaging group is informed by using an L1/L2 signaling channel (a PDCCH).Whether or not to make an L1/L2 signaling channel exist in radioresources transmitted from an MBMS dedicated cell has not beendetermined yet. In this embodiment, it is assumed that no L1/L2signaling channel exists in radio resources transmitted from an MBMSdedicated cell. However, it is preferable that a paging informing methodis unified as much as possible for a unicast cell, an MBMS/Unicast-mixedcell, and an MBMS transmission dedicated cell which exist within thesame mobile communication system which is called LTE. This is because byunifying a paging informing method, the mobile communication system canbe prevented from becoming complicated. In the following explanation,the number of paging groups (referred to as K_(MBMS) from here on) isconsidered as the parameter for discontinuous reception at the time ofMBMS reception.

Next, the “MBMS service selection”, which is described with reference toFIG. 16, will be explained more concretely. The mobile terminal, in stepST1730 of FIG. 9, checks the contents of a service included in the MBMSarea information in order to know whether or not a service which theuser desires is provided in a corresponding MBMS area. When the servicewhich the user desires is provided in the MBMS area in question, themobile terminal makes a transition to step ST1731. In contrast, when theservice which the user desires is not provided in the corresponding MBMSarea, the mobile terminal makes a transition to step ST1733. The mobileterminal, in step ST1731, receives a reference signal (RS) with a radioresource of the MBSFN area in question, and measures the received power(RSRP) of the reference signal. The mobile terminal then determineswhether or not the received power is equal to or higher than a thresholddetermined statically or semi-statically. The fact that the receivedpower is equal to or higher than the above-mentioned threshold showsthat the mobile terminal has high sensitivity enough to receive the MBMSservice, whereas the fact that the received power is lower than thethreshold shows that the mobile terminal does not have high sensitivityenough to receive the MBMS service. When the received power is equal toor higher than the above-mentioned threshold, the mobile terminal makesa transition to step ST1732, whereas when the received power is lowerthan the above-mentioned threshold, the mobile terminal makes atransition to step ST1733. The mobile terminal, in step ST1732, acquiresa frequency f(MBMS) dedicated to MBMS transmission and an MBSFN area IDwhich are required for the user to receive the desired MBMS service. Onthe other hand, the mobile terminal, in step ST1733, determines whetheror not another MBMS area receivable within the same frequency band(f(MBMS)) exists. When another MBMS area receivable within the samefrequency band (f(MBMS)) exists, the mobile terminal returns to stepST1730 and repeats the process. In contrast, when any other MBMS areareceivable within the same frequency band (f(MBMS)) does not exist, themobile terminal makes a transition to step ST1734. The mobile terminal,in step ST1734, determines whether or not another frequency exists inthe frequency list of the receivable MBSFN synchronization area, whichthe mobile terminal receives in step ST1708. When another frequencyexists in the frequency list, the mobile terminal returns to step ST1722and switches its synthesizer to the new frequency (f2(MBMS)), and thenrepeats the process. In contrast, when any other frequency does notexist in the frequency list, the mobile terminal returns to step ST1720and repeats the process. Instead of receiving the reference signal andmeasuring the received power in step 1731, the mobile terminal canactually receive the MBMS service (an MTCH and/or an MCCH) in the MBSFNarea in question. In this case, the user can determine whether themobile terminal provides receive sensitivity which he or she can permitby hearing or viewing decoded data. When the mobile terminal providesreceive sensitivity which he or she can permit, the mobile terminalmakes a transition to step ST1732, whereas when the mobile terminal doesnot provide receive sensitivity which he or she can permit, the mobileterminal makes a transition to step ST1733. Because the permissiblereceive sensitivity has differences among individuals, there can beprovided an advantage of making mobile terminals be further suited forusers.

FIG. 58 is a flow chart showing a unicast side measurement process. Themobile terminal, in step ST1753 of FIG. 58, determines whether a DRXperiod start time of the MBMS service has come by using the DRXinformation which the mobile terminal receives in step ST1729 of FIG.19. As a concrete example, the mobile terminal determines the SFN numberof the leading system frame at which the DRX period starts by using theDRX cycle length and the starting point value (DRX) which are an exampleof the parameters which the mobile terminal receives in step ST1729, anddetermines whether or not a DRX period start time has come on the basisof the SFN mapped onto the BCCH (broadcast control channel) or the like.When no DRX period start time has come yet, the mobile terminal makes atransition to step ST1772. In contrast, when a DRX period start time hascome, the mobile terminal makes a transition to step ST1754. The mobileterminal, in step ST1754, determines whether or not the DRX period starttime is in a measurement period in the MBMS/Unicast-mixed cell receivedin step ST1705. When the DRX period start time is not in a measurementperiod, the mobile terminal makes a transition to step ST1772. Incontrast, when the DRX period start time is in a measurement period, themobile terminal makes a transition to step ST1755. The mobile terminal,in step ST1755, receives a downlink signal of the MBMS/Unicast-mixedcell by changing the frequency set to the frequency converting unit 1107thereof (the synthesizer) to change the center frequency to f(Unicast).The mobile terminal, in step ST1756, carries out a measurement on theside of the unicast (i.e., a measurement of a unicast cell and/or anMBMS/Unicast-mixed cell). As values which the mobile terminal actuallymeasures, the RSRPs, RSSIs, etc. of the serving cell and a neighboringcell can be considered. The information about the neighboring cell canbe broadcast, as neighboring cell information (a list), from the servingcell.

The mobile terminal, in step ST1757, judges whether or not are-selection (a cell re-selection) of the serving cell is neededaccording to the result of the measurement in step ST1756. As an exampleof a criterion of the judgment, there can be considered whether theresult of the measurement of one cell among neighboring cells exceedsthe result of the measurement of the serving cell. When no re-selectionis needed, the mobile terminal makes a transition to step ST1771. Incontrast, when a re-selection is needed, steps ST1758 and ST1759 arecarried out. Abase station (a new serving cell: New serving cell) whichis newly selected as the serving cell in step ST1758 broadcasts themeasurement period length, the discontinuous reception cycle length, andthe tracking area information (the TA information) to mobile terminalsbeing served thereby by using the BCCH (broadcast control channel), likein the case of step ST1705. The mobile terminal, in step ST1759,receives and decodes the BCCH from the new serving cell to receive themeasurement period length, the discontinuous reception cycle length, andthe TA information. The mobile terminal, in step ST1760, checks to seewhether or not the TA information of the serving base station receivedin step ST1759 is included in the current tracking area list (TA List)which is stored in the protocol processing unit 1101 or the control unit1110 thereof. When the TA information is included in the currenttracking area list, the mobile terminal makes a transition to stepST1771. In contrast, when the TA information is not included in thecurrent tracking area list, the mobile terminal performs step ST1761. Anexplanation of steps ST1761 to ST1770 will be omitted because it is thesame as that of steps ST1710 to ST1719. The mobile terminal, in stepST1771, moves to the frequency layer dedicated to MBMS transmission bychanging the frequency set to the frequency converting unit 1107 thereofto change the center frequency to f(MBMS).

Through the “unicast side measurement” process in steps ST1753 toST1771, the mobile terminal can carry out a measurement of a unicastcell and/or an MBMS/Unicast-mixed cell even if the mobile terminal isreceiving an MBMS service in the frequency layer dedicated to MBMStransmission. Accordingly, there is provided an advantage of making itpossible for a mobile terminal currently receiving an MBMS service in afrequency layer dedicated to MBMS transmission to ensure the mobility inunicast cells and/or MBMS/Unicast-mixed cells. As a result, there can beprovided an advantage of becoming able to ensure the mobility in MBMSdedicated cells in which no uplink channel exists by way of anMBMS/Unicast-mixed cell. Furthermore, a mobile terminal currentlyreceiving a service in a frequency layer dedicated to MBMS transmissionbecomes able to carryout downlink synchronization establishment througha measurement with a unicast cell or an MBMS/Unicast-mixed cell atmeasurement periods, too. As a result, there can be provided anadvantage of enabling a mobile terminal to implement even transmissionof a message in a unicast/mixed frequency layer with a short controldelay time.

Next, the “MTCH reception”, which is described with reference to FIG.16, will be explained more concretely. The mobile terminal, in stepST1772 of FIG. 59, determines whether the current time is an MCCHreceiving one of the number of the MBSFN area from which the mobileterminal is receiving an MBMS from the MCCH scheduling information. Thatis, the mobile terminal determines whether the current time is an MCCHreceiving one by using the scheduling of the MCCH (multicast controlchannel) received in step ST1725. More specifically, the mobile terminaldetermines the SFN number of the leading one of system frames onto whichthe MCCH is mapped by using the MCCH repetition period length and thestarting point value which are an example of the parameters which themobile terminal receives in step ST1725, and determines whether or notit is the leading one of system frames onto which the MCCH is mapped onthe basis of an SFN mapped onto the BCCH or the like to determinewhether it is the SFN number of the leading one of system frames ontowhich the MCCH is mapped. When the current time is a one of receivingthe MCCH, the mobile terminal makes a transition to step ST1840. Incontrast, when the current time is not a one of receiving the MCCH, themobile terminal makes a transition to step ST1841. The mobile terminal,in step ST1840, carries out reception and decoding of the MCCH. Afterthat, the mobile terminal makes a transition to step ST1842. The mobileterminal, in step ST1841, determines whether the current time is a oneof receiving the MTCH by using the scheduling of the MCCH received instep ST1725 and/or the MBMS area information received in step ST1729.When the current time is a one of receiving the MTCH, the mobileterminal makes a transition to step ST1843. In contrast, when thecurrent time is not a one of receiving the MTCH, the mobile terminalmakes a transition to step ST1753. The mobile terminal, in step ST1842,determines whether the current time is a one of receiving the MTCH byusing the scheduling of the MCCH received in step ST1725 and/or the MBMSarea information received in step ST1729. When the current time is a oneof receiving the MTCH, the mobile terminal makes a transition to stepST1843. In contrast, when the current time is not a one of receiving theMTCH, the mobile terminal makes a transition to step ST1794. The mobileterminal, in step ST1843, carries out reception and decoding of theMTCH. After that, the mobile terminal makes a transition to step ST1794.

The mobile terminal, in step ST1794 of FIG. 59, measures the quality ofreception of the MBMS service which the mobile terminal is receiving.The mobile terminal receives a reference signal (RS) with the radioresources of the MBSFN area in question, and measures the received power(RSRP). The mobile terminal then determines whether or not the receivedpower is equal to or higher than a threshold determined statically orsemi-statically. The fact that the received power is equal to or higherthan the above-mentioned threshold shows that the mobile terminal hashigh sensitivity enough to receive the MBMS service, whereas the factthat the received power is lower than the threshold shows that themobile terminal does not have high sensitivity enough to receive theMBMS service. When the received power is equal to or higher than theabove-mentioned threshold, the mobile terminal makes a transition tostep ST1795, whereas when the received power is lower than theabove-mentioned threshold, the mobile terminal makes a transition tostep ST1796. Instead of receiving the reference signal and measuring thereceived power in step 1794, the mobile terminal can actually receiveand decode the MBMS service (an MTCH and/or an MCCH) of the MBSFN areain question. In this case, the user can determine whether the mobileterminal provides receive sensitivity which he or she can permit byhearing or viewing decoded data. When the mobile terminal providesreceive sensitivity which he or she can permit, the mobile terminalmakes a transition to step ST1795, whereas when the mobile terminal doesnot provide receive sensitivity which he or she can permit, the mobileterminal makes a transition to step ST1796. Because the permissiblereceive sensitivity has differences among individuals, there can beprovided an advantage of making mobile terminals be further suited forusers. The mobile terminal, in step ST1795, checks to see the user'sintention. When the user desires to succeedingly receive the MBMSservice which the mobile terminal is receiving, the mobile terminalmakes a transition to step ST1753. In contrast, when the user desires toend the reception of the MBMS service which the mobile terminal isreceiving, the mobile terminal ends the processing. The mobile terminal,in step ST1796, determines whether there exists another MBMS area inwhich the mobile terminal can receive the MBMS service within the samefrequency band (f(MBMS)). When another MBMS area receivable within thesame frequency band exists, the mobile terminal returns to step ST1730and repeats the process. In contrast, when any other MBMS areareceivable within the same frequency band does not exist, the mobileterminal makes a transition to step ST1797. The mobile terminal, in step1797, determines whether or not there is another frequency in thefrequency list of the receivable MBSFN synchronization area received instep ST1708. When another frequency exists in the frequency list, themobile terminal returns to step ST1722 and switches its synthesizer to anew frequency (f2(MBMS)), and then repeats the process. In contrast,when any other MBMS area receivable within the same frequency band doesnot exist, the mobile terminal ends the processing. Also in thisEmbodiment, like in the case of Embodiment 2, the method of including,as identifiers of each mobile terminal, a mobile terminal identifierused in a unicast/mixed frequency layer and a mobile terminal identifierused in a frequency layer dedicated to MBSFN transmission can be used.

In accordance with the mobile communication system disclosed above, themethod of selecting a desired service in a frequency layer dedicated toMBMS transmission and the mobile communication system which enables themethod to be implemented therein can be disclosed.

Next, a variant (variant 1) will be explained. In the 3GPP, it has beendebated that a base station (cell) in an MBSFN synchronization area canconstruct a plurality of MBSFN areas. However, as mentioned previously,any detailed decision about a method of multiplexing MBSFN areas has notbeen made in the current 3GPP. In this variant 1, a concrete example ofthe multiplexing method of multiplexing MBSFN areas in such a case willbe described with the object of disclosing the method of selecting adesired service in a frequency layer dedicated to MBMS transmission andthe mobile communication system which enables the method to beimplemented therein, which are a challenge of the present invention. Anexplanation will be made focusing on a portion different from Embodiment11, and the explanation of the same portion as Embodiment 11 will beomitted hereafter.

In Embodiment 11, the method of, when configuring the PMCH of each MBSFNarea, carrying out either time division multiplexing (TDM) or codedivision multiplexing (CDM) for the PMCH of each MBSFN area is disclosedabove. In this variant 1, a method of, when configuring the PMCH of eachMBSFN area, carrying out both time division multiplexing (TDM) and codedivision multiplexing (CDM) for each MBSFN area. The configuration ofthe PMCH provided for each MBSFN area is shown in FIG. 63. In FIG. 63,both time division multiplexing (TDM) and code division multiplexing(CDM) are used for each MBSFN area. A cell #n1 is one located in theMBSFN area 1, a cell #n2 is one located in the MBSFN area 2, and a cell#n3 is one located in the MBSFN area 3. Furthermore, the cells #1, #2,and #3 also belong to an MBSFN area 4. FIG. 28 is an explanatory drawingshowing a plurality of MBSFN areas which construct an MBSFNsynchronization area, and is an explanatory drawing showing an MBSFNarea covering a plurality of MBSFN areas. In FIG. 28, four MBSFN areas 1to 4 exist in a single MBSFN synchronization area (MBSFN SynchronizationArea). Among the four MBSFN areas, the MBSFN area 4 covers the MBSFNareas 1 to 3. Code division multiplexing of the PMCHs of the MBSFN areas1, 2, and 3 is carried out, and time division multiplexing of the PMCHsof the MBSFN areas 1, 2, and 3 and the PMCH of the MBSFN area 4 iscarried out. Because the cell #n1 belongs to the MBSFN area 1, the PMCHcorresponding to the MBSFN area 1 is transmitted at a time. The PMCH istransmitted on an MBSFN subframe because the PMCH is transmitted via amulti-cell transmission scheme in each MBSFN area.

A set of MBSFN frames to which MBSFN subframes are allocated is referredto as an “MBSFN frame cluster” (MBSFN frame cluster). In the MBMSdedicated cell, all subframes in an MBSFN frame can be MBSFN subframesused for multi-cell transmission. The length of each of the repetitionperiods at which the MBSFN frame cluster corresponding to a certainMBSFN area is repeated is expressed as the “MBSFN frame clusterrepetition period” (MBSFN frame cluster repetition period). An MCH whichis a transport channel for MBMS is mapped onto the PMCH, and either orboth of a logical channel MCCH which is control information for MBMS anda logical channel MTCH which is data for MBMS are mapped onto the MCH.The MCCH and the MTCH can be divided in time and mapped onto the PMCH,and can be further divided in time and mapped onto a physical area whichis transmitted via a multi-cell transmission scheme. For example, theMCCH and the MTCH can be mapped onto different MBSFN subframes which arethe physical area onto which they are mapped as a result. The MCCH canbe mapped onto each MBSFN frame cluster, or only the MTCH can be mappedonto each MBSFN frame cluster. In a case in which only the MTCH ismapped onto the PMCH, the repetition period of the MCCH differs from therepetition period of the MBSFN frame cluster. Furthermore, there is acase in which a plurality of MCCHs are mapped onto each MBSFN framecluster. The length of each of the repetition periods at which the MCCHis repeated is expressed as the “MCCH repetition period 1”.

In FIG. 63, MCCH1 is MBMS control information for the MBSFN area 1, andMTCH1 is MBMS data for the MBSFN area 1. Because the cell #n1 belongs tothe MBSFN area 1 and the MBSFN area 4, time division multiplexing of thePMCH of the MBSFN area 1 and the PMCH of the MBSFN area 4 is carriedout. Similarly, because the cell #n2 belongs to the MBSFN area 2 and theMBSFN area 4, time division multiplexing of the PMCH of the MBSFN area 2and the PMCH of the MBSFN area 4 is carried out, and because the cell#n3 belongs to the MBSFN area 3 and the MBSFN area 4, time divisionmultiplexing of the PMCH of the MBSFN area 3 and the PMCH of the MBSFNarea 4 is carried out. Because multi-cell transmission of the PMCH ofthe MBSFN area 4 is carried out in the MBSFN area 4, the transmission ofthe PMCH in each of the cells #n1, #n2, and #n3 is carried out at thesame time. By thus using the method of carrying out both time divisionmultiplexing and code division multiplexing for the PMCH of each MBSFNarea, for example, time division multiplexing can be used for MBSFNareas which overlap one another and code division multiplexing can beused for MBSFN areas which do not overlap one another. Therefore, ascompared with the case of using only time division multiplexing, theefficiency of the radio resources can be improved because code divisionmultiplexing is used. Furthermore, as compared with the case of usingonly code division multiplexing, the mutual interference among MBSFNareas which overlap one another can be reduced and receive errorsdetected in MBMS data received by each mobile terminal can be reduced.

Hereafter, a concrete example of step ST1725 of FIG. 18 will be shown.In a first step, each of the mobile terminals carries out blinddetection of a P-SCH (a primary synchronization channel) in theabove-mentioned sequence for exclusive use. Therefore, each of themobile terminals which has blind-detected the P-SCH can carry out 5ms-timing detection. Furthermore, the P-SCH is transmitted via amulti-cell transmission scheme. Base stations located in the MBSFNsynchronization area are synchronized with one another for transmissionof the P-SCH is targeted for the base stations included in thesynchronization area. In a second step, each of the mobile terminalscarries out blind detection of an S-SCH. Each of the mobile terminalswhich has blind-detected the S-SCH can know 10 ms-timing detection(frame synchronization) and the MBSFN area ID. Furthermore, the S-SCH istransmitted via a multi-cell transmission scheme. In this variant, eachbase station belongs to a plurality of MBSFN areas. Therefore, a problemis that which MBSFN area is shown by the ID of the MBSFN area mappedonto the S-SCH. In this variant, it is assumed that the ID of the MBSFNarea mapped onto the S-SCH is the one of either one of MBSFN areas towhich each base station belongs. It is further assumed that the ID isthe one of the smallest (covered) one of the plurality of MBSFN areas towhich each base station belongs. Therefore, the multi-cell transmissionof the S-SCH is targeted for base stations included in each coveredMBSFN area. Each of the mobile terminals receives the BCCH by using thescrambling code related to the MBSFN area ID acquired in the secondstep. By decoding the BCCH, each of the mobile terminals can acquire thescheduling of the MCCH. Furthermore, the BCCH is transmitted via amulti-cell transmission scheme. Since each of the mobile terminals usesthe scrambling code acquired in the second step, the BCCH is the onefrom each covered MBSFN area. Therefore, the multi-cell transmission ofthe BCCH is targeted for base stations included in each covered MBSFNarea. Each of the mobile terminals can acquire the scheduling of theMCCH, the system bandwidth at f(MBMS), the number of transmissionantennas at f(MBMS), etc. by decoding the BCCH.

Hereafter, the scheduling of the MCCH will be further examined. Becausethe MBSFN synchronization area is synchronous in time, the P-SCH istransmitted at the same time within of the MBMS dedicated cell in theMBSFN area 1, the MBMS dedicated cell in the MBSFN area 2, and the MBMSdedicated cell in the MBSFN area 3. Furthermore, assuming that theabove-mentioned sequence exclusively used for the frequency layerdedicated to MBMS transmission is used, the sequences of the P-SCHs inall the MBSFN areas are the same as one another. Therefore, in the MBSFNsynchronization area, identical information is transmitted at the sametime by using the P-SCH. As mentioned above, it is considered that anMBSFN area ID is transmitted by using the S-SCH. In this case, by usingthe S-SCH, information different for each MBSFN area is transmitted atthe same time in the MBSFN synchronization area. In this case, all theMBMS dedicated cells in each MBSFN area transmit identical informationat the same time. The S-SCH uses the same radio resources in frequencyand in time in the MBSFN synchronization area. Furthermore, because theS-SCH is used for a search for an MBSFN area ID related to each MBSFNarea scrambling code, the S-SCH cannot be multiplied by the scramblingcode of each MBSFN area. The configuration of making each base stationbelong to a plurality of MBSFN areas while following such the functionsof the S-SCH can be implemented by setting the ID of the MBSFN areamapped onto the S-SCH to the ID of the smallest one of the plurality ofMBSFN areas to which each base station belongs, as mentioned above, byassuming that there is no S-SCH specific to an MBSFN area covering otherMBSFN areas.

Furthermore, non-transmission of the S-SCH to the MBSFN area coveringthe other MBSFN areas means that what is necessary is just to transmitonly one type of S-SCH in overlapping MBSFN areas (e.g., the MBSFN areas1 and 4) in the geographical locations where the plurality of MBSFNareas overlap one another. As a result, the S-SCHs from the plural MBSFNareas can be prevented from interfering with one another. The mobilecommunication system transmits a BCCH multiplied by the scrambling coderelated to an MBSFN area ID which the mobile communication systeminforms by using the S-SCH. Therefore, in this case, by using the BCCH,information different for each MBSFN area covered is transmitted at thesame time in the MBSFN synchronization area. The contents of the BCCHare the same in all the MBMS-dedicated base stations in each MBSFN area.By decoding the BCCH, each of the mobile terminals can acquire thescheduling of the MCCH. An example of the scheduling of the MCCH has notbeen discussed in the 3GPP. In the present invention, an example of thescheduling of the MCCH will be shown.

Referring to FIG. 63, the scheduling of the MCCH in the case in which anMBSFN frame cluster is longer than the MCCH repetition period lengthwill also be explained. As the scheduling of the MCCH of the MBSFN areacovering the other MBSFN areas, e.g., the scheduling of the MCCH of theMBSFN area 4 of FIG. 28, two steps will be considered. In the followingexplanation, for the sake of simplicity, a case in which a mobileterminal is being served by a base station belonging to the MBSFN area 1and the MBSFN area 4 will be explained. In a first step, the MCCHscheduling of the MBSFN area 1 is informed by using the BCCH of theMBSFN area 1. In the present invention, an example of the scheduling ofthe MCCH will be shown. In the present invention, it is assumed that the“starting point value at the time when the MCCH is mapped”, the “MBSFNframe cluster repetition period length”, and the “MCCH transmissionfrequency during the MBSFN frame cluster repetition period” are informedfrom a cell to each terminal for the scheduling of the MCCH. Moreconcretely, an SFN (System Frame Number) is used for the indication ofthe starting point value. A concrete computation expression forcalculating the starting point value is given as follows.

The starting point value=(the SFN number of the leading one of systemframes onto which the MCCH is mapped in the MBSFN frame cluster) mod(the MBSFN frame cluster repetition period length)

More concretely, the MCCH transmission frequency (referred to asN_(MCCH) from here on) in the MBSFN frame cluster is used as the MCCHtransmission frequency within the MBSFN frame cluster repetition period.A concrete computation expression for calculating N_(MCCH) is expressedas follows.N _(MCCH)=the MBSFN frame cluster length/the MCCH repetition periodlength

In FIG. 63, the starting point value 1 of the MBSFN area 1 is 5 mod16=5, 21 mod 16=5, or . . . . The starting point value 2 of the MBSFNarea 2 is 5 mod 16=5, 21 mod 16=5, or . . . . The starting point valueof the MBSFN area 3 is the same as that of the MBSFN area 2. Then,N_(MCCH)1 of the MBSFN area 1 is 12/6=2, and N_(MCCH)2 of the MBSFN area2 is 12/4=3. In the case of the MBSFN area 3, N_(MCCH) is determinedsimilarly. Therefore, the parameters of the scheduling of the MCCH ofthe MBSFN area 1 are the MBSFN frame cluster repetition period length 1of “16”, the starting point value 1 of “5”, and N_(MCCH)1 of “2”. Atthis time, instead of informing N_(MCCH)1 as one of the parameters, theMBSFN frame cluster 1 and the MCCH repetition period length 1 can beinformed.

In a second step, the scheduling of the MCCH of the MBSFN area 4 isinformed by using the MCCH of the MBSFN area 1. The method ofdetermining the parameters of the scheduling of the MCCH is the same asthat in the case of FIG. 60 because the MBSFN frame cluster is smallerthan the MCCH repetition period length. The starting point value 4 ofthe MBSFN area 4 is 1 mod 16=1, 17 mod 16=1, or . . . . In the concreteexample of the scheduling of the MCCH, the MBSFN area ID of the MBSFNarea 4 covering the other MBSFN areas, as well as the parameters of theabove-mentioned MBSFN area 4 (the MCCH repetition period length 4 of“16” and the starting point 4 of “1”), are informed. Because it isassumed that no S-SCH dedicated to the MBSFN area 4 exists, it isnecessary to also inform the MBSFN area ID at this time.

More specifically, data transmitted from the MBSFN area 1 are providedas follows. The P-SCH which is the sequence exclusively used for thefrequency layer dedicated to MBMS transmission, the S-SCH1 onto whichthe MBSFN area ID1 and so on are mapped, a BCCH1 onto which the MCCHstarting point value 1 of “5”, the MBSFN frame cluster repetition periodlength 1 of “16”, N_(MCCH)1 of “2”, and so on are mapped, and which ismultiplied by the scrambling code 1, and an MCCH1 and an MTCH1 of theMBSFN area 1 each of which is multiplied by the scrambling code 1 aretransmitted. By using the MCCH1, the MBSFN area ID (the MBSFN area 4),and the MCCH starting point value 4 of “1” and the MCCH repetitionperiod length 4 of “16”, which are the data about the MCCH scheduling ofthe MBSFN area 4, are transmitted.

Like in the case of the MBSFN area 1, data which are transmitted fromthe MBSFN area 2 are provided as follows. The P-SCH which is thesequence exclusively used for the frequency layer dedicated to MBMStransmission, the S-SCH2 onto which the MBSFN area ID2 and so on aremapped, a BCCH2 onto which the MCCH starting point value 2 of “5”, theMBSFN frame cluster repetition period length 2 of “16”, N_(MCCH)2 of“3”, and so on are mapped, and which is multiplied by the scramblingcode 2, and an MCCH2 and an MTCH2 of the MBSFN area 2 each of which ismultiplied by the scrambling code 2 are transmitted. By using the MCCH2,the MBSFN area ID (the MBSFN area 4), and the MCCH starting point value4 of “1” and the MCCH repetition period length 4 of “16”, which are thedata about the MCCH scheduling of the MBSFN area 4, are transmitted. Asexplained previously, the data transmission from the MBSFN area 4 doesnot include transmission of the P-SCH and the S-SCH. In addition, whenit is not necessary to inform, as the system information about the MBSFNarea 4, any information other than what is transmitted by using the BCCHof each of the covered MBSFN areas (the MBSFN areas 1 to 3), thetransmission of the BCCH from the MBSFN area 4 can be omitted. As aresult, there can be provided an advantage of making effective use ofthe radio resources. An MCCH4 and an MTCH4 of the MBSFN area 4 each ofwhich is not multiplied by any scrambling code are transmitted. Each ofthe MCCH4 and the MTCH4 can be multiplied by a scrambling code specificto the MBSFN area 4. There can be provided an advantage of suppressingthe interference among the MBSFN areas. In this case, it is assumed thatthe scrambling code specific to the MBSFN area 4 is related with theMBSFN area ID of the MBSFN area 4, which is informed via the MCCH of theMBSFN area 1, 2, or 3. Accordingly, there can be provided an advantageof eliminating the necessity to carry out further signaling.

For the sake of simplicity, the example in which time divisionmultiplexing of the MCCH and the MTCH is carried out for each subframeis shown in FIG. 63. However, the present invention can be applied to acase in which another method of multiplexing the MCCH and the MTCH isused, and a case in which the time division multiplexing is carried outfor each of units other than each subframe. Even in the case in whicheach base station constructs a plurality of MBSFN areas in the mobilecommunication system explained above, the method of selecting a desiredservice in a frequency layer dedicated to MBMS transmission and themobile communication system which enables the method to be implementedtherein, which are a challenge of the present invention, can bedisclosed.

In the above-mentioned example, the service contents of the MBSFN area 4are included in the MBMS area information in the MCCH4. In this case,when transmitting the MCCH scheduling information about the MBSFN areacovering the other MBSFN areas (i.e., the MBSFN area 4, and refer toFIG. 28) by using the MCCHs of the covered MBSFN areas (the MBSFN areas1 to 3, and refer to FIG. 28), the service contents of the MBSFN area 4,as well as the scheduling information, can be informed. Accordingly,each mobile terminal (user) becomes able to grasp the service contentsof the plurality of MBSFN areas to which the base station belongs at thetime of decoding the MCCHs of the covered MBSFN areas. Therefore, therecan be provided an advantage of eliminating the necessity for eachmobile terminal to receive and decode in turn the MCCHs of the pluralityof MBSFN areas to which the base station belongs to make a selection ofan MBMS service, thereby reducing the control delay time occurring ineach mobile terminal. Concretely, each mobile terminal, in step ST1729of FIG. 19, receives the service contents of the covered MBSFN areas(the MBSFN areas 1 to 3, and refer to FIG. 28), and the service contentsof the MBSFN area covering the other MBSFN areas (the MBSFN area 4, andrefer to FIG. 28) by way of the MCCHs of the covered MBSFN areas (theMBSFN areas 1 to 3, and refer to FIG. 28). As a result, each mobileterminal can grasp the contents of receivable MBMS services at thecurrent location (location). Each mobile terminal, in step ST1730 ofFIG. 19, checks an MBSFN area in which the content of a desired MBMSservice is being transmitted.

Furthermore, there can be considered a method of informing the servicecontents of the MBSFN area 4 by using the BCCH of the MBSFN area 1 forthe MCCH scheduling of the MBSFN area 4. As a result, because a mobileterminal receiving a service of the MBSFN area 4 does not have to carryout the process of receiving and decoding the MCCH of the MBSFN area 1,there can be provided an advantage of reducing the control delay timeoccurring in the mobile terminal. The method of using, as the MCCHscheduling, the above-mentioned starting point, the MBSFN frame clusterrepetition period length, and N_(MCCH) (alternatively, the MBSFN framecluster length and the MCCH repetition period length) can be appliedalso to a case in which the MCCH exists multiple times in the MBSFNframe cluster when time division multiplexing of the MBSFN areas iscarried out (refer to FIG. 60).

Variant 2

In Embodiment 11, the service contents of each MBSFN area are includedin the MBMS area information in the MCCH. As an alternative, the servicecontents of each MBSFN area, as well as the scheduling of the MCCH, canbe informed by using the BCCH. As a result, each mobile terminal (user)can grasp the service contents of the MBSFN areas to which the basestation belongs at the time of decoding the BCCH. As a result, becauseeach mobile terminal can determine whether a desired service existsbefore receiving and decoding the MCCH and does not have to carry outthe process of receiving and decoding the MCCH of any MBSFN area inwhich the desired service is ongoing, there can be provided an advantageof reducing the control delay time occurring in each mobile terminal.Concretely, each mobile terminal, in step ST1725 of FIG. 18, receivesthe service contents of the MBSFN areas. As a result, each mobileterminal can grasp the contents of receivable MBMS services at thecurrent location (location). After that, each mobile terminal checks tosee whether or not the service which the user desires is ongoing in theMBSFN area in question prior to step ST1729 of FIG. 19. When the desiredservice is ongoing, each mobile terminal makes a transition to stepST1729. Each mobile terminal makes a transition to step ST1731 afterstep ST1729. In contrast, when the desired service is not ongoing, eachmobile terminal omits the processes of steps ST1729 and ST1731, and thenmakes a transition to step ST1733.

Furthermore, the MBMS area information, the DRX information, and theparameter for discontinuous reception at the time of MBMS receptionmapped, which are mapped onto MCCH, can also be informed by using theBCCH. As a result, the MCCH becomes unnecessary, and the efficiency ofthe radio resources can be improved. Therefore, it becomes unnecessaryto inform the scheduling of the MCCH by using the BCCH, and theefficiency of the radio resources can be further improved. This variant2 can also be applied to variant 1. In this case, the same advantagescan be provided.

In the 3GPP, it has been also examined that single-cell transmission(Single-cell transmission) is applied in a frequency layer dedicated toMBMS transmission. As a method of applying single-cell transmission in afrequency layer dedicated to MBMS transmission, there can be considereda method of implementing single-cell transmission in an MBSFN areahaving a one-cell configuration. However, a concrete method ofimplementing single-cell transmission in an MBSFN area having a one-cellconfiguration has not been decided. Assuming that only one base stationbelongs to an MBSFN area in the above-mentioned explanation, a mobilecommunication system in which single-cell transmission is implemented inan MBSFN area having a one-cell configuration can be disclosed.

Embodiment 12

In this Embodiment 12, a mobile communication system which differs fromEmbodiment 11 mainly in an MBMS search will be disclosed. A flow ofprocessing carried out by the mobile communication system in accordancewith this Embodiment 12 is nearly the same as that shown in FIGS. 16 and17 of Embodiment 11. An explanation of the flow will be made focusing ona portion different from Embodiment 11. Each unicast cell or eachMBMS/Unicast-mixed cell, in step ST1707 of FIG. 17, broadcasts one ormore frequencies at which an MBMS service is ongoing, other than thosein the current unicast/mixed frequency layer, to mobile terminals beingserved thereby by using the BCCH. That is, each unicast cell or eachMBMS/Unicast-mixed cell broadcasts one or more frequencies (f(MBMS)s) ofa receivable MBSFN synchronization area. In addition, each unicast cellor each MBMS/Unicast-mixed cell broadcasts either or both of the systembandwidth at each frequency f(MBMS) and the number of transmissionantennas at each frequency f(MBMS). Each of the mobile terminals, instep ST1708 of FIG. 17, receives either or both of the system bandwidthat each frequency f(MBMS) and the number of transmission antennas ateach frequency f(MBMS) by receiving and decoding the BCCH from theserving base station. Information showing whether or not each frequencyf(MBMS) falls within either the frequency layer constructed of aunicast/MBMS mixed cell or the frequency layer constructed of an MBMSdedicated cell can also be informed to each of the mobile terminals. Asa result, each of the mobile terminals becomes able to change itsoperation between the frequency layer constructed of a unicast/MBMSmixed cell, and the frequency layer constructed of an MBMS dedicatedcell. A concrete example of the operation is an MBMS search operation.In a unicast/MBMS mixed cell, since a unicast service is provided, it isdifficult to reduce the P-SCH, the S-SCH, and so on which are used forthe unicast service. Therefore, the method explained in Embodiment 11 isused for the MBMS search operation in the frequency layer constructed ofa unicast/MBMS mixed cell. In contrast, in an MBMS dedicated cell, sinceno unicast service is provided, there are fewer limitations on the MBMSdedicated cell as compared with a unicast/MBMS mixed cell. Therefore, aprocess as will be explained hereafter is applied to the MBMS searchoperation in the frequency layer constructed of an MBMS dedicated cell.

In Embodiment 12, steps ST1723 to ST1725 of FIG. 18 are changed as shownin FIG. 64. FIG. 64 is a flow chart showing a method of searching for anMBMS. In FIG. 64, an MBMS GW 802, more specifically, an MBMS CP 802-1,in step ST2201, informs the contents of a physical channel (referred toas a main PMCH) which is transmitted via a multi-cell transmissionscheme in an MBSFN synchronization area to an MCE 801. Since the mainPMCH is transmitted via a multi-cell transmission scheme in an MBSFNsynchronization area, the same information needs to be transmitted byusing the same radio resources from a base station in the MBSFNsynchronization area. Therefore, the MBMS GW informs schedulinginformation such as radio resources (a frequency, a time, etc.), as wellas the notification of the contents of the main PMCH in step ST2201.

FIG. 65 is an explanatory drawing showing the configuration of the mainPMCH in an MBSFN synchronization area. FIG. 65 shows a case where PMCHsrespectively provided for MBSFN areas are multiplexed by using timedivision multiplexing and code division multiplexing. A cell #n1 is onelocated in an MBSFN area 1, a cell #n2 is one located in an MBSFN area2, and a cell #n3 is one located in an MBSFN area 3. Furthermore, thecells #1, #2, and #3 also belong to an MBSFN area 4. Code divisionmultiplexing of the PMCHs of the MBSFN areas 1, 2, and 3 is carried out,and time division multiplexing of the PMCHs of the MBSFN areas 1, 2, and3 and the PMCH of the MBSFN area 4 is carried out. Time divisionmultiplexing of the main PMCH and the PMCH of each MBSFN area is carriedout. In the cell #n1, time division multiplexing of the PMCH1 and thePMCH4 is carried out and time division multiplexing of the main PMCH andthem is further carried out because the cell #n1 belongs to the MBSFNarea 1 and the MBSFN area 4. The same goes for each of the cells #2 and#3. Because the main PMCH is transmitted via a multi-cell transmissionscheme in the MBSFN synchronization area, it is transmitted on an MBSFNsubframe which is SFN-combined. A set of MBSFN frames to which MBSFNsubframes are allocated is referred to as an “MBSFN frame cluster”. Inthe MBMS dedicated cell, all subframes in an MBSFN frame can be MBSFNsubframes used for multi-cell transmission. The length of each of therepetition periods at which the main PMCH is repeated is expressed to asthe main PMCH repetition period.

An MCH which is a transport channel for MBMS is mapped onto the mainPMCH. An MCCH which is a logical channel used for MBMS controlinformation and an MTCH which is a logical channel used for MBMS dataare mapped onto the MCH. The MCCH and the MTCH can be divided in timeand mapped onto the main PMCH, and can be further divided in time andmapped onto a physical area which is transmitted via a multi-celltransmission scheme. For example, the MCCH and the MTCH can be mappedonto different MBSFN subframes which are the physical area onto whichthey are mapped as a result. The MCCH can be mapped onto each MBSFNframe cluster via which the main PMCH is transmitted, or only the MTCHcan be mapped onto the MBSFN frame clusters. In a case in which only theMTCH exists in the main PMCH, the repetition period of the MCCH differsfrom the repetition period of the main PMCH. Furthermore, there is acase in which a plurality of MCCHs are mapped onto the MBSFN frameclusters via which the main PMCH is transmitted.

In FIG. 65, MCCH1 is MBMS control information for the MBSFN area 1, andMTCH1 is MBMS data for the MBSFN area 1. MCCH2 is MBMS controlinformation for the MBSFN area 2, and MTCH2 is MBMS data for the MBSFNarea 2. MCCH3 is MBMS control information for the MBSFN area 3, andMTCH3 is MBMS data for the MBSFN area 3. MCCH4 is MBMS controlinformation for the MBSFN area 4, and MTCH4 is MBMS data for the MBSFNarea 4. The MCCHs can be mapped onto the PMCHs respectively, or only theMTCHs can be mapped onto the PMCHs respectively. In the case in whichonly the MTCHs exist on the PMCHs respectively, the MCCH of each MBSFNarea can be mapped onto the main PMCH. As an alternative, the MCCH ofeach MBSFN area can be included as an information element of the MCCHmapped onto the main PMCH. Because the main PMCH is transmitted via amulti-cell transmission scheme in the MBSFN synchronization area, themain PMCH cannot be multiplied by an MBSFN-area-specific scrambling codein such a way that the PMCH is scrambled in each MBSFN area. This isbecause the main PMCH is transmitted from a cell in a different MBSFNarea at the same time, and therefore, when the main PMCH is multipliedby an MBSFN-area-specific scrambling code, the phase of this main PMCHtransmitted from each MBSFN area becomes random in the receiver of eachmobile terminal, and the receiver becomes unable to carry out SFNcombining of the main PMCH. Therefore, as shown above, by carrying outtime division multiplexing of the main PMCH and the PMCH of each MBSFNarea, the multiplication by the scrambling code specific to each MBSFNarea can be carried out on a per subframe basis while the multiplicationof only the main PMCH by the scrambling code specific to each MBSFN areacan be avoided. As a result, the main PMCH can be transmitted via amulti-cell transmission scheme in the MBSFN synchronization area, and,even if each mobile terminal is receiving or trying to receive any MBMSservice in this MBSFN synchronization area, the mobile terminal canreceive the main PMCH and can also acquire an SFN gain. The main PMCH isnot multiplied by the scrambling code specific to each MBSFN area, asmentioned above, though the main PMCH can be multiplied by the MBSFNsynchronization area specific scrambling code. In this case, theinterference from any cell in any other MBSFN synchronization area canbe suppressed, and receive errors detected in the MBMS service receivedby each mobile terminal can be reduced. The MBSFN synchronization areaspecific scrambling code can be defined statically (Static) orsemi-statically (Semi-Static), and can be then mapped onto the BCCH fromthe serving base station and informed to each of the mobile terminals instep ST1705.

Furthermore, the scheduling of the radio resources (a frequency, a time,etc.) of the main PMCH in step ST2201 of FIG. 64 will be explained. Afrequency, a band, etc. are provided as a concrete example of thescheduling of the frequency. A concrete example of the scheduling of thetime will be explained with reference to FIG. 65. Hereafter, it will beconsidered that the starting point value of the time when the main PMCHis mapped and the main PMCH repetition period length are informed forthe scheduling of the main PMCH. More concretely, an SFN (System FrameNumber) is used for the indication of the starting point value. Aconcrete computation expression for calculating the starting point valueof the main PMCH is given as follows. The starting point value of themain PMCH=(the SFN number of the leading one of system frames onto whichthe main PMCH is mapped) mod (the main PMCH repetition period length)

In FIG. 65, the starting point value of the main PMCH is 1 mod 11=1, 12mod 11=1, or . . . , and the parameters of the scheduling of the mainPMCH are the main PMCH repetition period length 1 of “11” and the mainPMCH starting point value of “1”.

Next, a concrete example of the contents of the main PMCH in step ST2201of FIG. 64 will be explained. As a concrete example of the informationinformed via the main PMCH, the numbers (IDs or identifiers) of all theMBSFN areas existing in the MBSFN synchronization area, the schedulingof the MCCH of each MBSFN area, DRX information, etc. can be provided.Because an explanation of the details of the DRX information is the sameas that shown in Embodiment 11, the explanation of the details of theDRX information will be omitted hereafter. The DRX information can betransmitted via the MCCH of each MBSFN area, and the same advantages canbe provided. As an alternative, the DRX information can be mapped ontothe BCCH of the serving cell and transmitted to each of the mobileterminals in step ST1705 of FIG. 17, and the same advantages can beprovided. Furthermore, even when the DRX information is determinedstatically, the same advantages can be provided. When the DRXinformation is determined statically, because it becomes unnecessary tobroadcast the DRX information from the network side to each of themobile terminals, there can be provided an advantage of making effectiveuse of the radio resources. The scheduling of the MCCH of each MBSFNarea is also carried out, like in the case of Embodiment 11. In FIG. 65,the scheduling information (parameters) of the MCCH of the MBSFN area 1are the MCCH repetition period 1 of “11” and the MCCH starting pointvalue 1 of “2”. The scheduling information (parameters) of the MCCH ofeach of the MBSFN areas 2, 3, and 4 is the same as that of the MBSFNarea 1. By mapping the MCCH schedulings of all the MBSFN areas in theMBSFN synchronization area onto the main PMCH, it becomes able totransmit the main PMCH via a multi-cell transmission scheme in the MBSFNsynchronization area.

The MCE, in step ST2202 of FIG. 64, receives the contents and schedulinginformation of the main PMCH from the MBMS GW. The MCE, in step ST2203,transmits the contents and scheduling information of the main PMCH toeach base station belonging to an MBSFN area which the MCE controls.Each base station, in step ST2204, receives the contents and schedulinginformation of the main PMCH. Each base station, in step ST2205,transmits the main PMCH according to the scheduling from the MCE.

Each of the mobile terminals, in step ST2206, makes a search for anMBMS. Each of the mobile terminals especially, in step ST2206, carriesout timing synchronization. Prescribed information is mapped onto a partof the main PMCH. Accordingly, each of the mobile terminals establishestiming synchronization by carrying out blind detection of the prescribedinformation mapped on the above-mentioned main PMCH.

Prescribed information (or a symbol or a sequence) can be mapped onto aphysical radio resource which is a part of the main PMCH. Accordingly,each of the mobile terminals can establish timing synchronization bycarrying out blind detection of the prescribed information (or a symbolor a sequence) mapped onto the physical radio resource. As analternative, the prescribed information (or a symbol or a sequence) canbe mapped onto a physical radio resource adjacent in time to or separatein time by a fixed offset from the main PMCH. Accordingly, each of themobile terminals can establish timing synchronization by carrying outblind detection of the prescribed information (or a symbol or asequence) mapped onto the physical radio resource.

In Embodiment 11, the timing synchronization is carried out by using theP-SCH and S-SCH in a frequency layer dedicated to MBMS transmission. Incontrast, in this Embodiment 12, the timing synchronization can beimplemented without using the P-SCH and S-SCH. Therefore, the use of theMBMS search method in accordance with this Embodiment 12 makes itpossible to reduce the P-SCH and S-SCH in a frequency layer dedicated toMBMS transmission (an MBMS-dedicated base station). Accordingly, therecan be provided an advantage of making effective use of the radioresources. Each of the mobile terminals, in step ST2207, carries outreception and decoding of the main PMCH detected in step ST2206. Each ofthe mobile terminals receives all the MBSFN area IDs, the scheduling ofthe MCCH of each MBSFN area, and the DRX information which are mappedonto the main PMCH.

Furthermore, the information mapped onto the BCCH in Embodiment 11includes the scheduling of the MCCH, the system bandwidth at f(MBMS),the number of transmission antennas at f(MBMS), and the SFN. Inaccordance with Embodiment 12, the MCCH scheduling is mapped onto themain PMCH. Furthermore, the scheduling of the MCCH, the system bandwidthat f(MBMS) and the number of transmission antennas at f(MBMS) are mappedonto the BCCH in each of the unicast cell and the unicast/MBMS mixedcell. By mapping the SFN onto the main PMCH, it becomes able to reducethe frequency of BCCH transmission from the frequency layer dedicated toMBMS transmission (the MBMS dedicated cell). Accordingly, there can beprovided an advantage of making effective use of the radio resources.Furthermore, it becomes unnecessary to receive the BCCH which is achannel different from the main PMCH in order to receive the SFN.Therefore, there can be provided an advantage of reducing the controlload on each of the mobile terminals, reducing the control delay timeoccurring in each of the mobile terminals, and achieving low powerconsumption in each of the mobile terminals. Because the processes instep ST1726 and subsequent steps of FIG. 18 are the same as those ofEmbodiment 11, the detailed explanation of them will be omittedhereafter. The control information for MBMS service which each of themobile terminals, in step ST1729 of FIG. 19, acquires by receiving anddecoding the MCCH of each MBSFN area includes MBMS area information anda parameter for discontinuous reception at the time of MBMS reception.As a concrete example of the MBMS area information, there can beconsidered information about the frame structure of each area (i.e., thestructure of an MBSFN frame cluster and an MBSFN subframe), servicecontents, and modulation information about the MTCH, etc.

Steps ST1723 to ST1725 of FIG. 18 explained in Embodiment 11 can beused. In this case, the scheduling information of the main PMCH can benotified, instead of the scheduling of the MCCH shown in Embodiment 11,by using the BCCH from the frequency layer dedicated to MBMStransmission. Accordingly, the blind detection in step ST2206 of FIG. 64becomes unnecessary. As a result, there can be provided an advantage ofreducing the processing load on each of the mobile terminals, andachieving low power consumption in each of the mobile terminals.

Next, variant 1 of this Embodiment will be explained. In Embodiment 12,the service contents of each MBSFN area are included in the MBMS areainformation in the MCCH. As an alternative, the service contents of eachMBSFN area, as well as the scheduling of the MCCH, can be informed byusing the main PMCH. As a result, each mobile terminal (user) can graspthe service contents of each MBSFN areas at the time of decoding themain PMCH. As a result, because each mobile terminal can determinewhether a desired service exists before receiving and decoding the MCCHand does not have to carry out the process of receiving and decoding theMCCH of any MBSFN area in which the desired service is ongoing, therecan be provided an advantage of reducing the control delay timeoccurring in each mobile terminal. Concretely, each mobile terminal, instep ST2207 of FIG. 64, receives the service contents of each MBSFNarea. Accordingly, each mobile terminal can grasp the service contentsof each MBSFN area. After that, each mobile terminal searches for anMBSFN area in which the service which the user desires is ongoing priorto step ST1729 of FIG. 19. When an MBSFN area in which the service whichthe user desires is ongoing exists, each mobile terminal carries outstep ST1729 according to the MCCH scheduling of the MBSFN area so as toreceive the MCCH of the MBSFN area. In contrast, when an MBSFN area inwhich the service which the user desires is ongoing does not exist, eachmobile terminal omits the processes of steps ST1729, ST1730, and ST1733of FIG. 19, and then makes a transition to step ST1734.

Furthermore, the MBMS area information, and the parameter fordiscontinuous reception at the time of MBMS reception mapped, which aremapped onto each MCCH, can also be informed by using the main PMCH. As aresult, the MCCH of each MBSFN area becomes unnecessary, and theefficiency of the radio resources can be improved (refer to FIG. 66).Therefore, it becomes unnecessary to inform the scheduling of the MCCHof each MBSFN area by using the main PMCH, and the efficiency of theradio resources can be further improved. Furthermore, because eachmobile terminal does not have to receive the MCCH of each MBSFN area,there can be provided an advantage of reducing the load on each of themobile terminals and achieving low power consumption in each of themobile terminals.

Next, variant 2 of this Embodiment will be explained. Instead of stepsST2201 to ST2207 of FIG. 64 in Embodiment 12, the following processesare carried out in variant 2. A flow of processing carried out by amobile communication system in accordance with this variant 2 is nearlythe same as that explained in Embodiment 12. An explanation of the flowwill be made focusing on a portion different from Embodiment 12. Invariant 2, steps ST2201 to ST2207 of FIG. 64 are changed as shown inFIG. 67. Because an explanation of steps ST1726 to ST1728 is the same asthat of steps ST1726 to ST1728 shown in FIGS. 18 and 19, the explanationof steps ST1726 to ST1728 of variant 2 will be omitted hereafter. Eachof the mobile terminals, in step ST2501 of FIG. 67, makes a search foran MBMS. Each of the mobile terminals, in step ST2501, carries outtiming synchronization. Prescribed information is mapped onto a part ofthe MCCH of each MBSFN area. Accordingly, each of the mobile terminalsestablishes timing synchronization by carrying out blind detection ofthe prescribed information about each MBSFN area. Prescribed information(or a symbol or a sequence) is mapped onto a physical radio resourcewhich is a part of an MBSFN subframe onto which the MCCH of each MBSFNarea is mapped. Accordingly, each of the mobile terminals can establishtiming synchronization by carrying out blind detection of the prescribedinformation (or a symbol or a sequence) mapped onto the physical radioresource. As an alternative, the prescribed information (or a symbol ora sequence) can be mapped onto a physical radio resource adjacent intime to or separate in time by a fixed offset from the MCCH of eachMBSFN area. Accordingly, each of the mobile terminals can establishtiming synchronization by carrying out blind detection of the prescribedinformation (or a symbol or a sequence) mapped onto the physical radioresource. The prescribed information used for the blind detection is notmultiplied by a scrambling code specific to each MBSFN area. As aresult, each of the mobile terminals becomes able to carry out the blinddetection. Therefore, the multiplexing method of multiplexing MBSFNareas has a high degree of compatibility with this variant 2 when themultiplexing method is a time division multiplexing one (refer to FIG.60). In Embodiment 11, the timing synchronization is carried out byusing the P-SCH and S-SCH in a frequency layer dedicated to MBMStransmission. In contrast, in this Embodiment 12, the timingsynchronization can be implemented without using the P-SCH and S-SCH.Therefore, the use of the MBMS search method in accordance with thisEmbodiment 12 makes it possible to reduce the P-SCH and S-SCH in afrequency layer dedicated to MBMS transmission (an MBMS-dedicated basestation). Furthermore, in Embodiment 12, the timing synchronization iscarried out by using the main PMCH. In contrast, in this variant 2, thetiming synchronization is carried out by using the MCCH of each MBSFNarea. As a result, the timing synchronization is carried out by usingonly the MCCH of an MBSFN area which each mobile terminal can receive atthe current location (location). Therefore, as compared with Embodiment11 and Embodiment 12, the frequency with which it is determined, in stepST1731, that each mobile terminal does not have high sensitivity enoughto receive the MBMS service is reduced. As a result, there can beprovided an advantage of being able to reduce the control delay timeoccurring in the mobile communication system. Each of the mobileterminals, in step ST2502 of FIG. 67, carries out reception and decodingof the MCCH of the MBSFN area detected in step ST2501. Each of themobile terminals receives the control information for MBMS service whichis mapped onto the MCCH. As an example of the control information, thereare MBMS area information, a parameter for discontinuous reception atthe time of MBMS reception, etc. As the MBMS area information, there canbe considered the frame structure of each area (the structure of anMBSFN frame cluster and an MBSFN subframe), service contents, modulationinformation about the MTCH, etc.

Each of the mobile terminals, in step ST1730 of FIG. 19, checks servicecontents included in the MBMS area information. When the service whichthe user desires is ongoing in the MBMS area in question, each of themobile terminals makes a transition to step ST1731. In contrast, whenthe service which the user desires is not ongoing in the MBMS area, eachof the mobile terminals makes a transition to step ST2503. Each of themobile terminals, in step ST1731, receives an RS with a radio resourceof the MBSFN area in question, and measures the received power (RSRP) ofthe RS. Each of the mobile terminals then determines whether or not thereceived power is equal to or higher than a threshold determinedstatically or semi-statically. The fact that the received power is equalto or higher than the above-mentioned threshold shows that each of themobile terminals has high sensitivity enough to receive the MBMSservice, whereas the fact that the received power is lower than thethreshold shows that each of the mobile terminals does not have highsensitivity enough to receive the MBMS service. When the received poweris equal to or higher than the threshold, each of the mobile terminalsmakes a transition to step ST1732, whereas when the received power islower than the threshold, each of the mobile terminals makes atransition to step ST2503. Each of the mobile terminals, in step ST2503,makes a search for an MBMS by using the same method as that shown instep ST2501. Each of the mobile terminals, in step ST2504, determineswhether or timing synchronization is established with either anotherMBSFN area for which the determination that the desired service is notongoing is made in step 1730, or another MBSFN area other than the MBSFNarea for which the determination that each mobile terminal does not havehigh sensitivity enough to receive the MBMS service is made in stepST1731. In a case in which timing synchronization with another MBSFNarea is established, each of the mobile terminals makes a transition tostep ST2502. In contrast, in a case in which no timing synchronizationwith another MBSFN area is established, each of the mobile terminalsmakes a transition to step ST1734. Furthermore, the DRX information, theSFN and so on, which are mapped onto the main PMCH, can also be informedby using each MCCH. As a result, the main PMCH becomes unnecessary, andthe efficiency of the radio resources can be improved.

Embodiment 13

In this Embodiment 13, a mobile communication system which differs fromthat of Embodiment 11 mainly in DRX information will be disclosed. Aflow of processing carried out by the mobile communication system inaccordance with this Embodiment 13 is nearly the same as that shown inFIGS. 16 and 17 of Embodiment 11. An explanation of the flow will bemade focusing on a portion different from Embodiment 11. In Embodiment11, one DRX period is provided in an MBSFN synchronization area (referto FIG. 62). In contrast, in this Embodiment 13, one DRX period isprovided in an MBSFN area. A DRX period in accordance with thisEmbodiment 13 means a time period during which transmission of an MBMSservice from a corresponding MBSFN area is in an off state. A concreteexample of DRX information will be explained with reference to FIGS. 68and 69. First, an explanation will be made with reference to FIG. 68.FIG. 68 is an explanatory drawing showing the configuration of a PMCH ofeach MBSFN area. The length of a DRX period and that of a DRX cycle fora mobile terminal currently receiving an MBMS service from an MBSFN area1 are expressed as the DRX period length 1 and the DRX cycle length 1respectively. A concrete example of parameters of the DRX informationwill be explained. Concretely, the DRX period length, the DRX cyclelength, and a starting point value (DRX) can be considered as theparameters. The DRX period length 1 is “6” radio frames. Furthermore,the DRX cycle length 1 is “9” radio frames. In addition, an SFN is usedfor the indication of the starting point value (DRX) at which the DRXperiod starts. A concrete computation expression for calculating thestarting point value (DRX) is given as follows.

The starting point value (DRX)=(the SFN number of the leading systemframe at which the DRX period starts) mod (the DRX cycle length), andthe starting point value 1 (DRX) is 4 mod 9=4, 13 mod 9=4, or . . . .

The length of a DRX period and that of a DRX cycle for a mobile terminalcurrently receiving an MBMS service from an MBSFN area 2 are expressedas the DRX period length 2 and the DRX cycle length 2 respectively. TheDRX period length 2 is “6” radio frames. Furthermore, the DRX cyclelength 2 is “9” radio frames. The starting point value 2 (DRX) is 7 mod9=7, 16 mod 9=7, or . . . . Similar DRX information is provided for amobile terminal currently receiving an MBMS service from an MBSFN area3.

Next, an explanation will be made with reference to FIG. 69. The lengthof a DRX period and that of a DRX cycle for a mobile terminal currentlyreceiving an MBMS service from the MBSFN area 1 are expressed as the DRXperiod length 1 and the DRX cycle length 1 respectively. The DRX periodlength 1 is “4” radio frames. Furthermore, the DRX cycle length 1 is“16” radio frames. The starting point value 1 (DRX) is 1 mod 16=1, 17mod 16=1, or . . . . Similar DRX information is provided for a mobileterminal currently receiving an MBMS service from either the MBSFN area2 or the MBSFN area 3. The length of a DRX period and that of a DRXcycle for a mobile terminal currently receiving an MBMS service from anMBSFN area 4 are expressed as the DRX period length 4 and the DRX cyclelength 4 respectively. The DRX period length 4 is “12” radio frames.Furthermore, the DRX cycle length 4 is “16” radio frames. The startingpoint value 4 (DRX) is 5 mod 16=5, 21 mod 16=5, or . . . . Because in acase in which there is a main PMCH as explained in Embodiment 12, even amobile terminal currently receiving an MBMS service of either of theMBSFN areas needs to receive the main PMCH, a time period during whichthe main PMCH is transmitted is removed from the DRX period of eachMBSFN area.

Each mobile terminal becomes able to carry out a measurement of aunicast/mixed frequency layer by using a DRX period provided for eachMBSFN area. Accordingly, there can be provided an advantage of beingable to carry out management of the mobility of each mobile terminal viathe unicast/mixed frequency layer even if each mobile terminal isreceiving an MBMS service in a frequency layer dedicated to MBMStransmission comprised of an MBMS-dedicated base station for which nouplink exists, which is a challenge of the present invention.

Furthermore, in order to enable the length of each of periods at whichto carryout a measurement of the unicast/mixed frequency layer, thelength being informed from a network side, to be satisfied withouttransmitting information about the DRX cycle length and the DRX periodlength in the frequency layer dedicated to MBMS transmission, via one ofroutes, to a control device (a base station, an MME, a PDNGW, or thelike) on a side of the unicast/mixed frequency layer and withoutinterrupting the reception of the MBMS service, the following methodwill be disclosed in the present invention, like in the case ofEmbodiment 11.

One or more measurement periods in the unicast/mixed frequency layer aremade to be included in a DRX period in the frequency layer dedicated toMBMS transmission. As a result, even if any measurement period length isinformed (set) to each mobile terminal from a unicast cell or anMBMS/Unicast-mixed cell, when each mobile terminal carries out ameasurement of the unicast/mixed frequency layer during the DRX periodwhich is provided in the DRX cycle in the frequency layer dedicated toMBMS transmission, the measurement period length informed from thenetwork side can be satisfied. By using this method, any control deviceof an MBMS transmission dedicated cell (a base station, an MCE, an MBMSgateway, an eBNSC, or the like) does not have to inform the DRX cyclelength and the DRX period length in the MBMS transmission dedicated cellto control devices of a unicast cell and an MBMS/Unicast-mixed cell.Therefore, there is provided an advantage of enabling a mobile terminalcurrently receiving an MBMS service in a frequency layer dedicated toMBSFN transmission to carry out a measurement at measurement periods ofa length which a unicast cell or an MBMS/Unicast-mixed cell has informed(set) to the mobile terminal without interrupting the reception of theMBMS service, while preventing the mobile communication system frombecoming complicated, that is, avoiding addition of signaling onto thewireless interface or into the network. The DRX cycle in the frequencylayer dedicated to MBSFN transmission has a length which is either aminimum of the measurement period length which can be provided in theunicast/mixed frequency cell, or an integral submultiple of the minimum.In a case in which the measurement period length which can be set to amobile terminal currently receiving an MBMS service in the frequencylayer dedicated to MBMS transmission differs from the measurement periodlength which can be provided in the unicast/mixed frequency layer, theDRX cycle has a length which is equal to that of the measurement periodlength which can be set to a mobile terminal currently receiving an MBMSservice in the frequency layer dedicated to MBMS transmission, which isa minimum of the above-mentioned measurement period length, or which isan integral submultiple of the minimum of the above-mentionedmeasurement period length. Accordingly, a problem of the presentinvention can be solved.

Each mobile terminal, in step ST1729 of FIG. 19, receives DRXinformation. Because the DRX information differs for each MBSFN area,the mapping of the DRX information onto an MCCH of each MBSFN area canprevent each mobile terminal from receiving unnecessary information (theDRX information of another MBSFN area). As a result, there can beprovided an advantage of reducing the processing load on each mobileterminal, and achieving low power consumption in each mobile terminal.However, the mapping of the DRX information onto either a BCCH in thefrequency layer dedicated to MBMS transmission or the main PMCH canprovide the same advantages as those provided by Embodiment 13.

Compared with the mobile communication system disclosed in Embodiment11, the mobile communication system in accordance with Embodiment 13 canprovide the following advantages. In Embodiment 11, one DRX period isprovided in an MBSFN synchronization area (refer to FIG. 62). Inaccordance with the method in accordance with Embodiment 11, a DRXperiod is defined as a time period during which the transmission of anMBMS service from any of all MBSFN areas in an MBSFN synchronizationarea is in an off state. In contrast, in accordance with Embodiment 13,a DRX period is provided for each MBSFN area. More specifically, a DRXperiod 1 of an MBSFN area 1 is defined as a time period during which anyMBMS service is in an off state in the MBSFN area 1 while the DRX period1 is a time period during which any MBMS service can be carried out inanother MBSFN area 2. That is, it is not necessary to turn off MBMSservices in all MBSFN areas in an MBSFN synchronization area. Therefore,compared with Embodiment 11, Embodiment 13 can provide the advantage ofmaking further effective use of the radio resources.

Next, variant 1 of this Embodiment will be explained. Since one DRXperiod is provided in an MBSFN synchronization area in Embodiment 11,each mobile terminal becomes able to simultaneously receive MBMS datafrom MBSFN areas in an MBSFN synchronization area without adding anycontrol. In other words, when simultaneously receiving an MBMS servicefrom each MBSFN area, each mobile terminal (user) can freely select amethod of combining MBSFN areas. However, in accordance with Embodiment13, each mobile terminal cannot simultaneously receive MBMS servicesfrom MBSFN areas. A concrete example will be explained with reference toFIG. 70. The length of a DRX period and that of a DRX cycle for a mobileterminal currently receiving an MBMS service from an MBSFN area 1 areexpressed as the DRX period length 1 and the DRX cycle length 1respectively. The DRX period length 1 is “6” radio frames. Furthermore,the DRX cycle length 1 is “9” radio frames. The starting point value 1(DRX) at which the DRX period starts is equal to “4”. When a mobileterminal carries out a measurement of a unicast/mixed frequency layer byusing the DRX period length 1, like in the case of Embodiment 11, themobile terminal cannot receive any MBMS service from each of an MBSFNarea 2 and an MBSFN area 3, which is transmitted from a base stationduring a time period which overlaps the DRX period 1. Similarly, amobile terminal currently receiving an MBMS service from the MBSFN area2 cannot receive any MBMS service from each of the MBSFN area 1 and theMBSFN area 3 when carrying out a measurement of the unicast/mixedfrequency layer by using the method in accordance with Embodiment 13.The same goes for a mobile terminal currently receiving an MBMS servicefrom the MBSFN area 3.

As to a problem that each mobile terminal cannot simultaneously receivean MBMS service from each MBSFN area in a case in which one DRX periodis provided in each MBSFN area, a solution will be disclosed as follows.The network side informs simultaneously-receivable MBSFN areas to eachmobile terminal. Furthermore, the network side transmits the DRXinformation of each of the simultaneously-receivable MBSFN areas to eachmobile terminal. A concrete example of the DRX information will beexplained with reference to FIG. 70. In a case in which each mobileterminal receives an MBMS service from each of the MBSFN area 1 and theMBSFN area 2, the DRX period has a length equal to the DRX periodlengths (1+2)=[3]. In this case, the DRX cycle has a length equal to theDRX cycle lengths (1+2)=[9]. Furthermore, the starting point value (1+2)(DRX) at which the DRX period starts is 7 mod 9=7 or 16 mod 9=7, and thestarting point value 1+2 (DRX) is equal to [7]. In a case in which eachmobile terminal receives an MBMS service from each of the MBSFN area 1and the MBSFN area 3, the DRX period has a length equal to the DRXperiod lengths (1+3)=[3]. In this case, the DRX cycle has a length equalto the DRX cycle lengths (1+3)=[9]. Furthermore, the starting pointvalue (1+3) (DRX) at which the DRX period starts is 4 mod 9=4 or 13 mod9=4, and the starting point value (1+3) (DRX) is equal to [4].

Each mobile terminal, in step ST1729 of FIG. 19, receives the DRXinformation. A concrete example of the DRX information which each mobileterminal receives in step ST1729 is summarized in FIG. 71. FIG. 71[a]shows a concrete example of the DRX information mapped onto the MCCH ofthe MBSFN area 1. FIG. 71[b] shows a concrete example of the DRXinformation mapped onto the MCCH of the MBSFN area 2. FIG. 71[c] shows aconcrete example of the DRX information mapped onto the MCCH of theMBSFN area 3. In this case, each of the DRX period length and the DRXcycle length is expressed as a number of subframes. As an alternative,each of them can be expressed as a number of elements other thansubframes. Furthermore, the starting point value (DRX) is expressed asan SFN number. As an alternative, the starting point value can be set byusing another specifying method.

Furthermore, in order to enable the length of each of periods at whichto carry out a measurement of the unicast/mixed frequency layer, thelength being informed from the network side, to be satisfied withoutsending information about the DRX cycle length and the DRX period lengthin the frequency layer dedicated to MBMS transmission, via one ofroutes, to a control device (a base station, an MME, a PDNGW, or thelike) on a side of the unicast/mixed frequency layer and withoutinterrupting the reception of the MBMS service, the following methodwill be disclosed in the present invention, like in the case ofEmbodiments 11 and 13. One or more measurement periods in theunicast/mixed frequency layer are made to be included in a DRX period inthe frequency layer dedicated to MBMS transmission. Furthermore, the DRXcycle in the frequency layer dedicated to MBSFN transmission has alength which is either a minimum of the measurement period length whichcan be provided in the unicast/mixed frequency cell, or an integralsubmultiple of the minimum. In a case in which the measurement periodlength which can be set to a mobile terminal currently receiving an MBMSservice in the frequency layer dedicated to MBMS transmission differsfrom the measurement period length which can be provided in theunicast/mixed frequency layer, the DRX cycle has a length which is equalto that of the measurement period length which can be set to a mobileterminal currently receiving an MBMS service in the frequency layerdedicated to MBMS transmission, which is a minimum of theabove-mentioned measurement period length, or which is an integralsubmultiple of the minimum of the above-mentioned measurement periodlength. Accordingly, the problem of the present invention can be solved.

Since the network side transmits the information aboutsimultaneously-receivable MBSFN areas to each mobile terminal, eachmobile terminal can simultaneously receive an MBMS service from eachMBSFN area. The network side can provide an advantage of being able tosolve the problem of the present invention by transmitting, as well asthe information about simultaneously-receivable MBSFN areas, the DRXinformation at that time to each mobile terminal.

In this variant 1, the method of mapping the information aboutsimultaneously-receivable MBSFN areas and the DRX information at thattime onto the MCCH of each MBSFN area is disclosed. Instead of mappingthe information about simultaneously-receivable MBSFN areas and the DRXinformation at that time onto the MCCH of each MBSFN area, they can bemapped onto the BCCH in the frequency layer dedicated to MBMStransmission. In this case, the same advantages as provided by variant 1can be offered. As an alternative, the information aboutsimultaneously-receivable MBSFN areas and the DRX information at thattime can be mapped onto the main PMCH. In this case, the same advantagesas provided by variant 1 can be offered.

Variant 2

As to the problem that each mobile terminal cannot simultaneouslyreceive an MBMS service from each MBSFN area in a case in which one DRXperiod is provided in each MBSFN area, a solution different from variant1 will be disclosed as follows. The network side transmits the DRXinformation of each MBSFN area to each mobile terminal, and each mobileterminal determines the DRX information of an MBSFN area from which eachmobile terminal desires to receive simultaneously. Each mobile terminal,in step ST1729, receives the DRX information. FIG. 72 shows a concreteexample of the DRX information mapped onto the MCCH of each MBSFN areawhich is transmitted from the network side to each mobile terminal invariant 2 in the case of FIG. 70. As a concrete example of the DRXinformation, the MBSFN area number (ID), the service contents, the MBSFNframe cluster length, the MBSFN frame cluster repetition period length,and the starting point of the MBSFN frame cluster of each MBSFN area areinformed. Accordingly, there can be provided an advantage of enablingeach mobile terminal to determine the DRX information. In this case, inaddition to the DRX information, the service contents of each MBSFN areacan be informed. Accordingly, there can be provided an advantage ofenabling each mobile terminal to select an MBSFN area which the userdesires and from which each mobile terminal receives simultaneously byreceiving and decoding the MCCH from one MBSFN area.

Each mobile terminal, in step ST1730, determines the DRX information ofan MBSFN area which the user of each mobile terminal desires and fromwhich each mobile terminal receives simultaneously. A concrete examplewill be explained with reference to FIG. 72. For example, when the userof each mobile terminal desires simultaneous reception of a “weatherforecast” service and a “news” service, each mobile terminal determinesthe DRX information in simultaneous reception of the MBSFN area 1 andthe MBSFN area 2. A DRX period will be explained. In order to receivethe MBSFN area 1 and the MBSFN area 2, a time period during whichtransmission of the MBSFN area 1 and that of the MBSFN area 2 are notcarried out is expressed as a DRX period (1+2). A DRX cycle in which aDRX period (1+2)=3 is repeated will be explained with reference to FIGS.70 and 72. In order to receive the MBSFN area 1 and the MBSFN area 2, acycle in which a time period during which transmission of the MBSFN area1 and that of the MBSFN area 2 are not carried out is repeated isexpressed as a DRX cycle (1+2). The DRX cycle (1+2) has a length equalto the MBSFN frame cluster repetition period length 3, i.e., 9. Thestarting point of DRX will be explained. In order to receive the MBSFNarea 1 and the MBSFN area 2, the starting point value of the periodduring which transmission of the MBSFN area 1 and that of the MBSFN area2 are not carried out is expressed as the starting point (1+2) (DRX).The starting point (1+2) (DRX) is equal to 7.

Furthermore, in order to enable the length of each of periods at whichto carryout a measurement of the unicast/mixed frequency layer, thelength being informed from the network side, to be satisfied withoutsending information about the DRX cycle length and the DRX period lengthin the frequency layer dedicated to MBMS transmission, via one ofroutes, to a control device (a base station, an MME, a PDNGW, or thelike) on a side of the unicast/mixed frequency layer and withoutinterrupting the reception of the MBMS service, the following methodwill be disclosed. Each mobile terminal selects multiplexing of MBSFNareas in such a way that one or more measurement periods in theunicast/mixed frequency layer are included in a DRX period in thefrequency layer dedicated to MBMS transmission. Each mobile terminalalso selects multiplexing of MBSFN areas in such a way that the DRXcycle in the MBMS transmission dedicated cell has a length which iseither a minimum of the measurement period length which can be providedin the unicast/mixed frequency layer, or an integral submultiple of theminimum. In other words, each mobile terminal determines the DRXinformation, and does not select any combination of MBSFN areas in whichthe DRX cycle does not satisfy the above-mentioned requirements. In acase in which the measurement period length which can be set to a mobileterminal currently receiving an MBMS service in the frequency layerdedicated to MBMS transmission differs from the measurement periodlength which can be provided in the unicast/mixed frequency layer, theDRX cycle has a length which is equal to that of the measurement periodlength which can be set to a mobile terminal currently receiving an MBMSservice in the frequency layer dedicated to MBMS transmission, which isa minimum of the above-mentioned measurement period length, or which isan integral submultiple of the minimum of the above-mentionedmeasurement period length. Accordingly, the problem can be solved.

This variant 2 can provide the same advantages as those provided byvariant 1. Furthermore, in a case in which the number of MBSFN areas islarge and the number of combinations of MBSFN areas is large, variant 2requires a smaller amount of DRX information which is transmitted fromthe network side to each mobile terminal as compared with variant 1.Accordingly, there can be provided an advantage of making effective useof the radio resources.

In this variant 2, the method of mapping the information aboutsimultaneously-receivable MBSFN areas and the DRX information at thattime onto the MCCH of each MBSFN area is disclosed. Instead of mappingthe information about simultaneously-receivable MBSFN areas and the DRXinformation at that time onto the MCCH of each MBSFN area, they can bemapped onto the BCCH in the frequency layer dedicated to MBMStransmission. The same advantages as provided by variant 2 can beoffered. As an alternative, the information aboutsimultaneously-receivable MBSFN areas and the DRX information at thattime can be mapped onto the main PMCH. In this case, the same advantagesas provided by variant 2 can be offered.

Each of this Embodiment 13 and its variants can be applied to Embodiment11 and the variants of this embodiment, and Embodiment 12 and thevariants of this embodiment.

Embodiment 14

A problem to be solved by this invention will be explained withreference to FIG. 73. In FIG. 73, A denotes an L1/L2 signaling channel,and B denotes a resource for unicast transmission. Allocation of MBSFNsubframes in an MBMS/unicast-mixed cell has been studied as disclosed innonpatent reference 2. Multiplexing of a channel used for MBSFN(Multimedia Broadcast multicast service Single Frequency Network) and achannel used for other than MBSFN is carried out for each subframe, asdisclosed in nonpatent reference 1. Hereafter, a subframe used for MBSFNtransmission is referred to as an MBSFN subframe (MBSFN subframe). Inthe current 3GPP, it is determined that a mixed cell must not use one ortwo leading OFDM symbols of each subframe for unicast transmission in anMBSFN frame (subframe). In other words, anything other than one or twoleading OFDM symbols is a resource dedicated to MBMS transmission. InFIG. 73, this resource is expressed as a PMCH. On the other hand,nonpatent reference 1 discloses that a PCH is mapped onto a PDSCH or aPDCCH. Nonpatent reference 1 also discloses that a paging group uses anL1/L2 signaling channel (PDCCH) and that a precise identifier (UE-ID) ofa mobile terminal can be found on a PCH. Therefore, because a PCH usesan L1/L2 signaling channel, even an MBSFN frame can be mapped onto thePCH. On the other hand, in a case in which allocation of a downlinkradio resource to the next control information using the PCH is carriedout in an MBSFN frame, because the downlink radio resource in the samesubframe is used exclusively for MBMS transmission, there arises aproblem that the control information cannot be allocated to the samesubframe.

Nonpatent reference 3 has the following description on transmission of apaging signal to a mobile terminal. A PICH (Paging Indicator channel)showing that a paging signal destined for a mobile terminal belonging toa paging group is occurring is transmitted by using an L1/L2 signalingchannel. In order to determine whether or not the paging signal is theone destined therefor, the mobile terminal decodes the paging signal.The PCH can have one or more paging signals. The PICH is transmitted byusing an L1/L2 signaling channel. In other words, the PICH is positionedat one to three leading OFDM symbols of each subframe. On the otherhand, the PCH is mapped onto the PDSCH in the same subframes as those atwhich the PICH is positioned. The problem to be solved by the presentinvention also arises in the paging signal transmitting proceduredisclosed in nonpatent reference 3. That is, in a case in which an MBSFNsubframe is formed in an MBMS/unicast-mixed cell, the same subframes atthose at which the PICH is positioned is a resource dedicated to MBMStransmission even if the PICH is transmitted with the one or two leadingOFDM symbols of each of MBSFN subframes. Therefore, it is impossible totransmit the PCH onto which a paging signal for enabling each mobileterminal to determine whether or not the paging signal is destinedtherefor is mapped.

Nonpatent reference 4 has the following description about an equationused for determining a time when paging occurs (i.e., paging occasion:Paging occasion). This reference describes that in order to determine apaging occasion, two parameters: a paging interval length (correspondingto a discontinuous reception cycle length in a mixed frequency layer inaccordance with the present invention), and the number of pagingoccasions during the paging interval are necessary, and there are noother necessary parameters. Furthermore, the reference describes that asubframe in a radio frame in which a paging occasion occurs has a fixedvalue. However, nonpatent reference 4 has no description about a methodof determining a subframe in a radio frame for paging occasion ontowhich a paging signal is mapped. Furthermore, nonpatent reference 4 hasno description about a relationship between a subframe in a radio framefor paging occasion and an MBSFN subframe.

OFDM symbols other than the one or two leading OFDM symbols of eachMBSFN subframe are a resource dedicated to MBMS transmission. In a casein which a subframe in a radio frame for paging occasion is also atarget for allocation of an MBSFN subframe, any OFDM symbols other thanthe one or two leading OFDM symbols of the MBSFN subframe are a resourcededicated to MBMS transmission and cannot be used for paging processing.Because MBSFN subframes are not taken into consideration at all in theconventional paging processing method, there arises a problem that it isimpossible to apply the conventional paging processing method to pagingprocessing in an MBMS/unicast-mixed cell. In order to solve thisproblem, in this Embodiment 14, a determining method of determining aradio frame for paging occasion in consideration of an MBSFN subframewill be disclosed.

MBSFN subframes are configured, as shown in FIG. 3, in such a way as tobe allocated to each MBSFN frame (MBSFN frame). A repetition period(Repetition Period) is provided for MBSFN frame clusters, and an MBSFNframe cluster (MBSFN frame Cluster) is scheduled within each repetitionperiod. MBSFN subframes allocated to each MBSFN frame can be the same asone another, or can be different from one another. An allocation patternof MBSFN subframes within each repetition period (Repetition Period) isdetermined according to an MBSFN frame cluster. This allocation patternof MBSFN subframes is repeated at the above-mentioned repetitionperiods. In the example shown in the figure, the allocation pattern ofMBSFN subframes to each MBSFN frame is the same, and this results in asmaller number of bits required to show the subframe numbers of theMBSFN subframes compared with a case in which the allocation pattern ofMBSFN subframes to each MBSFN frame is not the same. Furthermore,although it is assumed that continuous MBSFN frames are provided in theexample shown in the figure, they are not necessarily continuous. In acase in which the MBSFN frames are continuous, the number of bitsrequired to show the frame numbers of the MBSFN frames can be reducedcompared with the case in which the MBSFN frames are not continuous.

The length of each of the repetition periods at which an MBSFN framecluster is repeated, and the allocation pattern of MBSFN frames and thatof MBSFN subframes within each of these repetition periods are mappedonto a broadcast control channel (BCCH) which is a logical channel, andthis broadcast control channel is further mapped onto a broadcastchannel (BCH) which is a transport channel and a physical broadcastchannel (PBCH) which is a physical channel, and is then informed to eachmobile terminal. Furthermore, self-cell information is mapped onto thebroadcast control channel (BCCH) which is a logical channel, and thischannel is further mapped onto a downlink shared channel (DL-SCH) whichis a transport channel and a physical downlink shared channel (PDSCH)which is a physical channel, and is then informed to each mobileterminal. On the other hand, the following computation expression can beconsidered as a determining method of determining a radio frame forpaging occasion.

“Paging occurrence radio frame” (Paging Occasion)=an identifier of eachmobile terminal (IMSI or the like) mod X+n×(the discontinuous receptioncycle length), where n: 0, 1, 2, or . . . , and Paging Occasion≦themaximum of SFN. SFN is an integer ranging from 0 to its maximum. X isthe number of radio frames in which paging occurs within a discontinuousreception cycle, and satisfies the following inequality: X≦thediscontinuous reception cycle length (a number of radio frames). Thevalue of X (a remainder value at X) is associated with a radio framenumber (SFN).

As shown from the above-mentioned equation, in a radio frame associatedwith the number X of paging occurrence radio frames, a paging occasionwill occur within a discontinuous reception cycle. In other words,occurrence of a paging occasion is repeated at discontinuous periodswith a pattern of radio frames being associated with X. Parametersrequired to derive a paging occasion, the identifier of each mobileterminal, the discontinuous reception cycle length, X, and so on aremapped onto the broadcast control channel (BCCH) which is a logicalchannel, and this broadcast control channel is further mapped onto thebroadcast channel (BCH) which is a transport channel and the physicalbroadcast channel (PBCH) which is a physical channel, and are theninformed to each mobile terminal. Furthermore, self-cell information ismapped onto the broadcast control channel (BCCH) which is a logicalchannel, and this channel is further mapped onto the downlink sharedchannel (DL-SCH) which is a transport channel and the physical downlinkshared channel (PDSCH) which is a physical channel, and is then informedto each mobile terminal.

As mentioned above, because any OFDM symbols other than the one or twoleading OFDM symbols of each MBSFN subframe are a resource dedicated toMBMS transmission, MBSFN subframes cannot be used for paging processing.Therefore, because MBSFN subframes are not taken into consideration atall in the conventional paging processing method, there arises a problemthat it is impossible to apply the conventional paging processing methodto paging processing in an MBMS/unicast-mixed cell. In order to solvethis problem, a method of preventing an MBSFN frame and a frame in whicha paging occasion occurs from being always the same radio frame will bedisclosed hereafter. Concretely, the length of each of the repetitionperiods (Repetition Periods) at which an MBSFN frame cluster is repeateddiffers from the discontinuous reception cycle length. Morespecifically, the length of the repetition period of MBSFN frameclusters is made not to be equal to the discontinuous reception cyclelength, or they are made not to have an integral multiple relationship.

An example will be shown below. Conventionally, the discontinuousreception cycle length is defined as 2^(a)×radio frame (the unit is anumber or time), where a is a positive integer. The value of a isdetermined by a base station or the network, and is informed to eachmobile terminal through a serving cell. In this case, the length of eachof the repetition periods (Repetition Periods) at which an MBSFN framecluster is repeated is given by the following deriving equation.

2^(b)×radio frame (the unit is a number or time), where b is a positiveinteger.

In this case, a≠b.

Using these definitions, the period length and the cycle length areprevented from becoming equal to each other, and, also when an initialradio frame number which is allocated for the first time (an offsetvalue) is the same, an MBSFN frame and a paging occasion can beprevented from always occurring at the same radio frame. Accordingly,the paging processing can be carried out in an MBMS/unicast-mixed cellin which MBSFN subframes exist. In the above-mentioned example, an MBSFNframe and a paging occasion can be prevented from always occurring atthe same radio frame. However, because the equations for deriving boththe period length and the cycle length are given by 2m×radio frame (m=aand b), they have an integral multiple relationship, and therefore anMBSFN frame and a paging occasion occur at the same radio frame once forevery plural times an MBSFN frame cluster is repeated.

In order to avoid this problem, the following equation for deriving eachof the period length and the cycle length can be provided as anotherexample.

S^(m)×radio frame (the unit is a number or time), where S is a primenumber and m is a positive integer.

For the length of the repetition period of MBSFN frame clusters and thediscontinuous reception cycle length, different S values are used.Because S is a prime number, an MBSFN frame and a paging occasion can beprevented from occurring at the same radio frame by using Ss havingdifferent values for the period length and the cycle lengthrespectively. Therefore, the frequency with which a frame in which anMBSFN frame occurs and a frame in which a paging occasion occur are thesame can be further reduced.

If an MBSFN frame and a paging occasion occurs at the same radio frame,a base station or the network makes the MBSFN frame a higher prioritythan the paging occasion at the radio frame to give a higher priority tocommunications of information for MBMS to transmit this information. Bypredetermining such priorities assigned to an MBSFN frame and a pagingoccasion, each mobile terminal can also understand which information istransmitted thereto via a radio frame in which an MBSFN frame and apaging occasion occur simultaneously, and can receive and decode theinformation. A higher priority can be assigned to either of an MBSFNframe and a paging occasion which occur simultaneously. In a case inwhich a higher priority is assigned to an MBSFN frame, each mobileterminal can receive an MBMS service without loss of MBMS data andwithout delay time. In a case in which a higher priority is assigned toa paging occasion, the length of time required to carry out an incomingcall process of sending an incoming call to each mobile terminal can bereduced, and a delay time occurring at the time of occurrence of anincoming call can be reduced.

The equation for deriving each of the period length and the cycle lengthin these examples can be determined statically. Two or more types ofequations can be prepared beforehand to derive each of the period lengthand the cycle length, and which one of them should be selected can bedetermined. As an alternative, a parameter indicating which one of thetwo or more types of the equation for deriving each of the period lengthand the cycle length should be selected can be provided. Each parameterused for selecting a deriving equation for each of the period length andthe cycle length can be determined statically, or can be determinedsemi-statically or dynamically. When each parameter is determinedsemi-statically or dynamically, each parameter is determined by a basestation or the network and is informed, via the serving cell, to eachmobile terminal by using a BCCH, an MCCH, or L1/L2 signaling. In a casein which two types of equations are prepared beforehand to derive eachof the period length and the cycle length, 1-bit information can be sentas each parameter used for selecting a deriving equation for each of theperiod length and the cycle length, so that each parameter can beinformed to each mobile terminal from a base station or the network witha minimum amount of information, and the use efficiency of the radioresources is improved.

A concrete example of a sequence diagram in a case of making anotification of information about allocation of MBSFN subframes andderiving a paging occasion onto which a paging signal is mapped is shownin FIG. 74. The serving cell, in step ST4001, transmits the systeminformation about the cell itself to mobile terminals being servedthereby. A concrete example of the system information transmitted to themobile terminals includes a measurement period length, tracking areainformation (TA information), and a discontinuous reception cyclelength. A parameter for discontinuous reception is included in thesystem information about the cell itself. By using the determiningmethod, as disclosed above, of determining a paging occasion occurrenceradio frame, the discontinuous reception cycle length is derived fromthis parameter for discontinuous reception. A concrete example of theparameter for discontinuous reception includes parameters for derivingthe discontinuous reception cycle length. The parameters for derivingthe discontinuous reception cycle length include a, m, S, theinformation showing which deriving equation is used, the number (X) ofpaging occasions (or the number of paging groups) within a discontinuousreception cycle, a relationship between the value of X (a remaindervalue at X) and a radio frame number (SFN). As a concrete example of theindication of the discontinuous reception cycle length, the number ofradio frames can be used. Each mobile terminal, in step ST4002, receivesthe system information about the self-cell from the serving cell. Theserving cell, in step ST4501, transmits the information about allocationof MBSFN subframes. In the current 3GPP, the following regardingallocation of MBSFN subframes has been discussed. The mapping positionof a reference signal in an MBSFN subframe as a radio resource differsfrom that of a reference signal in a subframe which is not an MBSFNsubframe as a radio resource. It has been debated that in order to carryout a more correct measurement using a reference signal, even a mobileterminal having no capability of receiving an MBMS service needs tograsp the information about allocation of MBSFN subframes in the servingcell (nonpatent reference 2). As a concrete example of the informationabout allocation of MBSFN subframes, a parameter for deriving therepetition period of MBSFN frame clusters and an MBSFN subframeallocation pattern within this repetition period can be considered. Byusing the determining method, as disclosed above, of determining therepetition period of MBSFN frame clusters, the repetition period ofMBSFN frame clusters is derived from the above-mentioned parameter forderiving the repetition period of MBSFN frame clusters. A concreteexample of the parameter for deriving the repetition period of MBSFNframe clusters includes b, m, S, and the information showing whichderiving equation is used which are the parameters for deriving therepetition period. A concrete example of the MBSFN subframe allocationpattern within this repetition period includes an MBSFN frame numberand/or an MBSFN subframe number within this repetition period. Eachmobile terminal, in step ST4502, receives the information aboutallocation of MBSFN subframes from the serving cell. Each mobileterminal, in step ST4503, determines a paging occasion. Each mobileterminal and the serving cell, in steps ST4503 and ST4504, determine aradio frame for paging occasion by using the same method respectively,as the mobile communication system. Each mobile terminal, in stepST4505, determines a subframe in the radio frame for paging occasion.The serving cell, in step ST4506, determines the subframe in the radioframe for paging occasion by using the same method as that which eachmobile terminal uses, as the mobile communication system.

As disclosed in this Embodiment 14, by preventing an MBSFN frame and aframe in which a paging occasion occurs from being always the same radioframe, the problem of the present invention can be solved and thereforea paging process in an MBMS/unicast-mixed cell in which MBSFN subframesexist can be carried out.

Next, variant 1 of this embodiment will be explained. In Embodiment 14,the length of the repetition period of MBSFN frame clusters is set insuch a way as to differ from the discontinuous reception cycle lengthfor paging occasion. The pattern of MBSFN frames within a repetitionperiod of an MBSFN frame cluster can be configured in such a way as notto be the same as that of occurrence of a radio frame for pagingoccasion within a discontinuous reception cycle. For example, the lengthof the repetition period of MBSFN frame clusters is set to 32 radioframes. The MBSFN frames within a repetition period having this lengthare the ones #0 to #7 (the first radio frame within a repetition periodhaving the length is the one #0). In this case, for example, by usingthe above-mentioned method of deriving a paging occasion, thediscontinuous reception cycle length is set to 32 radio frames, thenumber X of paging occurrence radio frames is set to 4, and therelationship between the remainder value at X and the radio frame numberis determined as follows.

The radio frame number is #8 when the remainder value of X=zero,

the radio frame number is #14 when the remainder value of X=1,

the radio frame number is #20 when the remainder value of X=2,

and the radio frame number is #26 when the remainder value of X=3.

In this case, the radio frame number of the first radio frame within adiscontinuous reception cycle is #0.

In the case in which the remainder value of X is brought intocorrespondence with the radio frame number in this way, the pattern ofMBSFN frames within a repetition period of an MBSFN frame cluster can beconfigured in such a way as not to be the same as that of occurrence ofa radio frame for paging occasion within a discontinuous receptioncycle. Therefore, because even if the length of the repetition period ofMBSFN frame clusters is the same as the discontinuous reception cyclelength for paging occasion, the pattern of MBSFN frames within arepetition period of an MBSFN frame cluster differs from that ofoccurrence of a radio frame for paging occasion within a discontinuousreception cycle, an MBSFN frame and a paging occasion can be preventedfrom always occurring at the same radio frame.

In this variant, although a radio frame in which a paging occasionoccurs is determined on the basis of an MBSFN frame, the MBSFN frame canbe inversely determined on the basis of the radio frame in which apaging occasion occurs. For example, what is necessary is just tostatically determine a radio frame in which a paging occasion occurs,and, when determining an MBSFN frame semi-statically or dynamically,make a radio frame within a discontinuous reception cycle which isdifferent from the radio frame in which a paging occasion occurs be theMBSFN frame. By determining the MBSFN frame in this way, it becomes ableto determine MBSFN subframes flexibly according to the data volume ofMBMS, and it also becomes able to increase the use efficiency of theradio resources. This method of statically determining a radio frame inwhich a paging occasion occurs, and then determining an MBSFN framesemi-statically or dynamically can be applied to Embodiment 14 andvariant 2. Furthermore, as the method of informing the parameters inaccordance with this variant, the method described in Embodiment 14 canbe applied.

By using the method of this variant 1, there is provided an advantage ofallowing the length of the repetition period of MBSFN frame clusters tobe the same as the discontinuous reception cycle length in addition tothe advantages provided by Embodiment 14. By making the length of therepetition period of MBSFN frame clusters be the same as thediscontinuous reception cycle length, the parameters informed from abase station or the network to each mobile terminal can be reduced andthe use efficiency of the radio resources can be improved.

In the above-mentioned example, a pattern of MBSFN frames within arepetition period of an MBSFN frame cluster is used. As an alternative,a pattern of allocation of MBSFN subframes within a repetition period(Repetition Period) can be provided. In this case, what is necessary isjust to let an MBSFN frame in which these MBSFN subframes are includedbe a pattern of MBSFN frames within a repetition period of an MBSFNframe cluster. Accordingly, the same advantages are provided.

Embodiment 15

In Embodiment 2, the method of transmitting a paging signal from a basestation during each MCCH repetition period (MCCH repetition period) orduring each paging signal presence or absence indicator repetitionperiod, and allowing a mobile terminal which receives the paging signalto carry out a discontinuous reception operation during either of thoserepetition periods. Hereafter, another new method will be disclosed as amethod of transmitting a paging signal. As also described is Embodiment2, in accordance with a conventional technology (W-CDMA system), themethod has the step of defining the number of S-CCPCHs (the number ofchannelization codes) onto which a PCH is mapped as the number ofgroups, and determining a time at which paging indication istransmitted, i.e., SFN (System Frame Number) by using an identifier(UE-ID or IMSI) of each mobile terminal, and discontinuous receptiontiming. However, there is still no disclosure of any method oftransmitting a paging signal in a frequency layer dedicated to MBMStransmission in an LTE system. In a frequency layer dedicated to MBMStransmission, because transmission is carried out via a multi-celltransmission scheme, and an arbitrary cell is also allowed to belong toa plurality of MBSFN areas, a method of transmitting a paging indicationbased on a conventional technology cannot be applied to a method ofmapping a paging signal onto which radio frame or which subframe.Furthermore, because an LTE system is not a CDM method, there is noconcept of the number of channelization codes, and it is thereforeimpossible to apply the conventional technology. Therefore, a method oftransmitting a paging signal in a frequency layer dedicated to MBMStransmission of an LTE system will be disclosed hereafter. Anexplanation will be made focusing on a portion different from Embodiment2. Portions which will not be explained specifically are the same asthose explained in

Embodiment 2

As a method of enabling an MBMS dedicated cell to transmit a pagingsignal in a frequency layer dedicated to MBMS transmission of an LTEsystem, a configuration of transmitting a paging signal via a radioframe corresponding to an MBSFN area to which this cell belongs isprovided. As a concrete example, a method of transmitting a pagingsignal in a case in which no overlapping (or covering) MBSFN areas existin each cell and MBSFN subframes corresponding to MBSFN areas areCDM-multiplexed, as shown in FIG. 40, will be disclosed. First, acomputation expression for determining a paging group will be disclosed.Ksf in the computation expression for determining a paging group (IMSImod Ksf) is the number of paging groups. A concrete example of the valueof Ksf is the number of MBSFN subframes in one radio frame. In a case inwhich the number of MBSFN subframes in one radio frame is 10, Ksf isequal to 10. In contrast, in a case in which the value of Ksf is thenumber of MBSFN subframes in one radio frame excluding MBSFN subframes#0 and #5 onto which an SCH is mapped, Ksf is equal to 8. By bringingthe value of Ksf (a remainder value at Ksf) into correspondence withsubframe numbers in one radio frame, each mobile terminal is enabled toknow onto which subframe in one radio frame the paging information aboutthe paging group to which the mobile terminal itself belongs is mappedfrom the value of the paging group determined according to theabove-mentioned equation.

Next, a correspondence about onto which radio frame the paging signaldestined for the group to which the mobile terminal itself belongs ismapped is established. A concrete example of a computation expressionfor determining the radio frame is given as follows.

“Paging occurrence radio frame” (Paging Occasion)=(IMSI or Ksf) mod (thediscontinuous reception cycle length in the frequency layer dedicated toMBMS transmission)+n×(the discontinuous reception cycle length in theMBMS transmission frequency layer), where n: 0, 1, 2, or . . . , andPaging Occasion≦the maximum of SFN. SFN is an integer ranging from 0 tothe maximum of SFN.

The “paging occurrence radio frame” (referred to as the paging occasion)shows SFN onto which the paging signal is mapped. As can be seen fromthis equation, the paging occasion can have any of all possible valuesranging from zero to the maximum of SFN. Therefore, compared with themethod disclosed in Embodiment 2, the number of MBSFN subframes ontowhich a paging signal is mapped, and the number of radio frames havingthe MBSFN subframes can be increased. Therefore, it becomes able toreduce the number of mobile terminals which are mapped onto one MBSFNsubframe, and therefore the physical area required to carry pagingsignals whose number is equal to the number of mobile terminals onto oneMBSFN subframe can be reduced. Furthermore, because it is not necessaryto determine the discontinuous reception cycle length in the MBMStransmission frequency layer depending on the length of each of theperiods at which the MCCH is transmitted, the system becomes able to setup the discontinuous reception cycle length with flexibility. Next, thephysical area onto which a paging signal is mapped will be described. Apaging signal is configured in such a way as to be transmitted via allradio frames corresponding to an MBSFN area to which a cell belongs. Themethod, as disclosed in Embodiment 8, of providing a physical channeldedicated to paging (DPCH) which is transmitted via a multi-celltransmission scheme in an MBSFN area, and carrying a paging signal onthis physical channel is applied. As shown in FIG. 42, the DPCH forcarrying a paging signal is provided in a part of MBSFN subframescorresponding to the MBSFN area. The DPCH can be formed in all the radioframes corresponding to the MBSFN area and formed in all the MBSFNsubframes in one radio frame, or can be formed in MBSFN subframes in oneradio frame excluding MBSFN subframes #0 and #5 onto which an SCH ismapped. In the case in which the DPCH can be formed in all the MBSFNsubframes in one radio frame, Ksf can be set to 10. In contrast, in thecase in which the DPCH can be formed in MBSFN subframes in one radioframe excluding MBSFN subframes #0 and #5 onto which an SCH is mapped,Ksf can be set to 8. When Ksf is the number of subframes in one radioframe, Ksf can have another value. Because the methods disclosed inEmbodiment 8 can be applied to a paging signal on the paging dedicatedchannel and the method of mapping the paging signal onto the pagingsignal dedicated channel, the explanation of them will be omittedhereafter.

By thus providing the method of transmitting a paging signal, and thechannel structure for carrying the paging signal, as mentioned above,there is provided an advantage of being able to transmit a paging signalvia all radio frames corresponding to an MBSFN area to which an MBMSdedicated cell belongs, and enable the MBMS dedicated cell to transmitthe paging signal in a frequency layer dedicated to MBMS transmission ofan LTE system.

As another concrete example, a method of transmitting a paging signal ina case of taking a DRX period into consideration will be disclosed. InEmbodiment 2, the method of providing a DRX period for measurements in aunicast/mixed frequency layer is disclosed in order to enablesynchronization maintenance, acquisition of broadcast information, andcell re-selection in the unicast/mixed frequency layer to transmit apaging signal in an MBMS transmission dedicated cell. Hereafter, themethod of transmitting a paging signal in the case in which the DRXperiod is provided and this DRX period is taken into consideration willbe shown. Because the detailed explanation about this DRX period isdisclosed in Embodiment 2, the detailed explanation will be omittedhereafter. In this concrete example, it is assumed that one DRX periodfor measurements in a unicast/mixed frequency layer is provided in anMBSFN synchronization area (MBSFN Synchronization Area). An example ofthe configuration of MBSFN subframes of each MBSFN area in each cell inthe case of also taking the DRX period into consideration is shown inFIG. 75. SFN is set to a value ranging from 0 to SFNmax, and the DRXperiod length is set to d radio frames. Each cell transmits data forMBMS via radio frames SFN=0 to SFNmax-d. The radio frames SFN=SFNmax-d+1to SFNmax correspond to the DRX period, and the transmission is in anoff state during this period. It is assumed that one DRX period isprovided in an MBSFN synchronization area, as mentioned above.Therefore, cells belonging to each MBSFN area enter the transmission offstate at the same time (SFN). A paging signal is transmitted via theradio frames SFN=0 to SFNmax-d via which data for MBMS is alsotransmitted while being mapped onto a DPCH disclosed in Embodiment 8.First, a computation expression for determining a paging group will bedisclosed. The computation expression for determining a paging group isshown below.

IMSI mod Ksf

Ksf is the number of paging groups. A concrete example of the value ofKsf is the number of MBSFN subframes in one radio frame. In a case inwhich the number of MBSFN subframes in one radio frame is 10, Ksf isequal to 10. In contrast, in a case in which the value of Ksf is thenumber of MBSFN subframes in one radio frame excluding MBSFN subframes#0 and #5 onto which an SCH is mapped, Ksf is equal to 8. By bringingthe value of Ksf into correspondence with subframe numbers in one radioframe, each mobile terminal is enabled to know onto which subframe inone radio frame the paging information about the paging group to whichthe mobile terminal itself belongs is mapped from the paging group.

Next, as to onto which radio frame the paging signal destined for thegroup to which the mobile terminal itself belongs is mapped, two methodswill be disclosed as concrete examples of a computation expression fordetermining the radio frame. First, a first one of them will bedisclosed. A paging occasion (Paging Occasion) is defined as follows.

Paging occasion=(IMSI div Ksf) mod (SFNmax−ΣDRX), the discontinuousreception cycle length in the frequency layer dedicated to MBMStransmission=SFNmax, where it is assumed that the paging occasion has avalue which is obtained by renumbering the radio frames except thosecorresponding to the DRX periods.

In this case, SFNmax is the maximum of SFN, and DRX is the sum of thelengths of all DRX periods which exist within the radio frames SFN=0 toSFNmax. That is, (SFNmax−ΣDRX) shows the number of radio frames exceptthose corresponding to the DRX periods. Therefore, as can be seen fromthis equation, SFN onto which the paging signal is mapped can have thevalue of a radio frame, except those corresponding to the DRX periods,in which MBSFN subframes of each MBSFN area exist. Furthermore, becausethe discontinuous reception cycle length is set to SFNmax, for eachmobile terminal, a paging occasion occurs once during a time periodcorresponding to the radio frames SFN ranging from zero to SFNmax. Byusing the method configured in this way, a paging signal can be disposedin an MBSFN subframe corresponding to an MBSFN area from which a mobileterminal is receiving or trying to receive an MBMS, and the mobileterminal can therefore receive the paging signal when receiving ortrying to receive the MBMS. Because the above-mentioned methods can beapplied as a method of configuring a physical area onto which the pagingsignal is mapped, and a method of mapping the paging signal onto apaging signal dedicated channel, the explanation of them will be omittedhereafter.

As to onto which radio frame the paging signal destined for the group towhich the mobile terminal itself belongs is mapped, the second methodwill be disclosed. The second method is the one of providing twodifferent discontinuous reception cycles in the frequency layerdedicated to MBMS transmission. One of them is a discontinuous receptioncycle in which discontinuous reception is repeated within the maximum ofSFN, and the other one is a discontinuous reception cycle in whichdiscontinuous reception is repeated for every maximum of SFN. A concretepaging occasion (Paging Occasion) is given as follows.

Paging Occasion=(IMSI div Ksf) mod (a discontinuous reception cyclelength #1 in the frequency layer dedicated to MBMS transmission)+n×(thediscontinuous reception cycle length #1 in the frequency layer dedicatedto MBMS transmission),

The discontinuous reception cycle length #1≦(SFNmax-ΣDRX) in thefrequency layer dedicated to MBMS transmission, and a discontinuousreception cycle length #2 in the frequency layer dedicated to MBMStransmission=SFNmax, where n: 0, 1, 2, or . . . , and ∀PagingOccasion≦(SFNmax-ΣDRX). It is assumed that the paging occasion has avalue which is obtained by renumbering the radio frames except thosecorresponding to the DRX periods.

In this case, the discontinuous reception cycle length #1 in thefrequency layer dedicated to MBMS transmission is the length of thediscontinuous reception cycle in which discontinuous reception isrepeated within the maximum of SFN. The discontinuous reception cyclelength #2 in the frequency layer dedicated to MBMS transmission is thelength of the discontinuous reception cycle in which discontinuousreception is repeated for every maximum of SFN. The discontinuousreception cycle length #2 in the frequency layer dedicated to MBMStransmission is set up in such a way that the pattern of the values ofradio frames between 0 and SFNmax which are determined in thediscontinuous reception cycle #1 in the frequency layer dedicated toMBMS transmission is repeated for every maximum of SFN in thediscontinuous reception cycle #2 in the frequency layer dedicated toMBMS transmission. By determining n in such a way that all the valueswhich the result of the determination the paging occasion can havebecome equal to or smaller than (SFNmax-ΣDRX), an opportunity totransmit paging is provided equally to each mobile terminal. If anopportunity to transmit paging does not have to be provided equally toeach mobile terminal, n can be determined to be n: 0, 1, 2, or . . . ,where Paging Occasion (SFNmax-ΣDRX).

By determining n in this way, there occurs a difference in the pagingopportunity for each mobile terminal, though there is no radio framewhich is not used for a notification of a paging signal, and each mobileterminal becomes able to have as many opportunities as possible toreceive a paging signal, and becomes able to reduce receive errorsoccurring in the paging signal, a delay time occurring its incoming calloperation, etc.

A concrete example of the setting of the discontinuous reception cyclelength #1 in the frequency layer dedicated to MBMS transmission will beshown.

For example, a×2^((k−1))≦SFNmax-ΣDRX, where a and k are positiveintegers, and a, a×2, a×2², . . . , and a×2^((k−1)) are provided ascandidates for the discontinuous reception cycle length #1 in thefrequency layer dedicated to MBMS transmission and one candidate can beselected from among them. The values of a and k can be selected in anupper layer, and can be informed to each mobile terminal via broadcastinformation from a cell in the unicast/mixed frequency layer or viabroadcast information from a cell in the MBMS dedicated frequency layer,or via an MCCH corresponding to an MBMS service in an MBSFN area whicheach mobile terminal is receiving or trying to receive, and each mobileterminal can determine the discontinuous reception cycle length on thebasis of the informed values. Also in this method, because theabove-mentioned methods can be applied as a method of configuring aphysical area onto which a paging signal is mapped, and a method ofmapping the paging signal onto a paging signal dedicated channel, theexplanation of them will be omitted hereafter.

A concrete example of the method of transmitting a paging signal in thecase of taking a DRX period into consideration is disclosed above. Inthe method of transmitting a paging signal in the case of taking a DRXperiod into consideration, the paging signal can be mapped onto MBSFNsubframes of a radio frame excluding MBSFN subframes corresponding tothe DRX periods. These MBSFN subframes can be all the MBSFN subframes ofa radio frame excluding MBSFN subframes corresponding to the DRXperiods, or can be some MBSFN subframes of a radio frame excluding MBSFNsubframes corresponding to the DRX periods.

A concrete example of the method of transmitting a paging signal in thecase of taking a DRX period into consideration is disclosed above. Themethod of providing two different discontinuous reception cycles in thefrequency layer dedicated to MBMS transmission can be applied to also acase in which MBSFN subframes corresponding to an MBSFN area areTDM-multiplexed. For example, in a case in which no overlapping MBSFNareas exist in each cell, and MBSFN subframes corresponding to an MBSFNarea are TDM-multiplexed and there is a DRX period, as shown in FIG. 39,the number of radio frames each having MBSFN subframes corresponding toan MBSFN area to which each cell belongs can be provided instead of(SFNmax-ΣDRX), and the number of MBSFN subframes in one radio frame canbe defined as Ksf. For example, in a case in which overlapping MBSFNareas exist in each cell, MBSFN subframes corresponding to an MBSFN areawhich does not overlap any other MBSFN area are CDM-multiplexed, andMBSFN subframes corresponding to an overlapping MBSFN area areTDM-multiplexed and there is a DRX period, as shown in FIG. 41, somemethods can be considered.

In a case in which a paging signal is transmitted on one MBSFN area towhich each cell belongs, the number of radio frames each having MBSFNsubframes corresponding to the MBSFN area can be provided instead of(SFNmax-ΣDRX), and the number of MBSFN subframes in one radio frame canbe defined as Ksf, like in the above-mentioned case. In a case in whicha paging signal is transmitted also in an MBSFN area (area 4) coveringother MBSFN areas, a DPCH can be provided in the subframes #0 and #5 ofthe covering MBSFN area, and can be transmitted after multiplied by thescrambling code of a covered MBSFN area (e.g., area 1). As disclosed inEmbodiment 2, because an SCH is transmitted via the subframes #0 and #5of MBSFN subframes corresponding to a covered MBSFN area, the scramblingcode or the reference signal (RS) of the MBSFN area 1 can be used.Therefore, by providing a DPCH in the subframes #0 and #5 of thecovering MBSFN area, and transmitting the DPCH after multiplying theDPCH by the scrambling code of the MBSFN area 1, it becomes able toprovide a DPCH in all the radio frames excluding the radio framescorresponding to the DRX periods. Therefore, (SFNmax-ΣDRX) can be usedjuts as it is, and Ksf can be set to two (corresponding to the subframes#0 and #5).

When there is no subframe by which the scrambling code of the MBSFN area(e.g., area 1) covered by the covering MBSFN area (area 4) ismultiplied, it is impossible to transmit the same paging signal via allthe radio frames excluding the radio frames corresponding to the DRXperiods. Therefore, a DPCH is provided in MBSFN subframes of only theMBSFN area 1 or the MBSFN area 4, and the paging signal is transmitted.In this case, the number of radio frames each having MBSFN subframescorresponding to either one of the MBSFN areas can be provided insteadof (SFNmax-ΣDRX), and the number of MBSFN subframes in one radio framecan be defined as Ksf, like in the case in which a paging signal istransmitted on one MBSFN area.

Furthermore, this method of transmitting a paging signal can be appliedto also the case in which MBSFN subframes corresponding to an MBSFN areaare TDM-multiplexed, as previously explained. The method can be appliedto even a case in which a DRX period is provided in the above-mentionedcase. By thus providing the method of transmitting a paging signal, andthe channel structure for carrying the paging signal, as mentionedabove, there is provided an advantage of being able to, even in a casein which a DRX period is provided in a frequency layer dedicated to MBMStransmission of an LTE system, enable an MBMS dedicated cell to transmita paging signal in the frequency layer dedicated to MBMS transmission.Furthermore, although the case in which a DRX period is provided for ause which enables synchronization maintenance, acquisition of broadcastinformation, and cell re-selection in a unicast/mixed frequency layer isdescribed above, the uses of a DRX period are not limited to thisexample. Because the method of transmitting a paging signal and thechannel structure for carrying the paging signal, which are disclosed inthis embodiment, can be applied to also another case in which a DRXperiod is provided, the unicast/mixed frequency layer, the frequencylayer dedicated to MBMS transmission, and, furthermore, another systemcan be made to coexist or can be shared, and there is provided anadvantage of being able to construct and make use of the mobilecommunication system with flexibility.

A flow of the processing carried out by the mobile communication systemdescribed in this embodiment will be explained. A portion different fromthe method disclosed in Embodiment 2 will be mainly shown. First, inaddition to information about the scheduling of an MCCH, such as an MCCHrepetition period (MCCH repetition period) length, and DRX informationfor measurement in a unicast/mixed frequency layer, parameters for thetime of discontinuous reception at the time of MBMS reception, morespecifically, the discontinuous reception cycle length in the frequencylayer dedicated to MBMS transmission, the discontinuous reception cyclelengths #1 and #2 in the frequency layer dedicated to MBMS transmission,a, k, and Ksf have to be informed to each mobile terminal. All of thesepieces of information do not have to be transmitted, and necessaryparameters have only to be informed according to the paging group usedand the computation expression for determining a paging occasion (pagingoccasion). These parameters for the time of discontinuous reception atthe time of MBMS reception, as well as the information about thescheduling of the MCCH, can be informed to each mobile terminal, via aBCCH, from the MBMS dedicated cell in steps ST1723 and ST1724. As analternative, the parameters for the time of discontinuous reception atthe time of MBMS reception, as well as the MBMS area information, theDRX information for measurement in the unicast/mixed frequency layer,and the number of paging groups, can be informed to each mobileterminal, via an MCCH, from the MBMS dedicated cell in steps ST1728 andST1729. In this case, the parameters required for the paging occasiondetermining computation expression have only to be informed, though thisembodiment is not limited to the parameters. A parameter showing whichtiming (SFN) each mobile terminal should receive when performing adiscontinuous reception operation can be informed instead. As a concreteexample, an explicit receiving timing (SFN) and a discontinuousreception cycle length can be informed.

Next, a discontinuous reception preparing operation performed by eachmobile terminal will be explained. The discontinuous reception preparingoperation performed by each mobile terminal in this embodiment is shownin FIG. 76. ST6201 is carried out instead of ST1735 shown in FIG. 19.Each mobile terminal, in ST6201, makes preparations for discontinuousreception at the time of MBMS reception by using the parameters for thetime of discontinuous reception at the time of MBMS reception receivedin step ST1729. Concretely, each mobile terminal determines theabove-mentioned paging group and paging occasion of the mobile terminalitself by using the number Ksf of paging groups, the discontinuousreception cycle lengths in the frequency layer dedicated to MBMStransmission, a, k, the DRX information, etc. which are received in stepST1729. Furthermore, each mobile terminal uses an identification ID(UE-ID or IMSI) of the mobile terminal itself for the determination ofthe paging group and paging occasion. SFNmax has only to bepredetermined in the system, and the predetermined value is used.

Next, the discontinuous reception process at the time of MBMS receptionwill be explained. The discontinuous reception process at the time ofMBMS reception in this embodiment is shown in FIG. 77. Each mobileterminal, in step ST6301, determines whether the current time is a timeof receiving a paging signal from the result of the determination of thepaging occasion carried out in step ST6201. More concretely, each mobileterminal determines whether or not it is the SFN number of the pagingoccasion destined for the mobile terminal itself. When it is not the SFNnumber of the paging occasion, each mobile terminal makes a transitionto ST6306. Each mobile terminal, in ST6306, determines whether thecurrent time is a time of receiving the MCCH by using the scheduling ofthe MCCH received in ST1725. More concretely, each mobile terminaldetermines whether it is the SFN number of the leading one of systemframes onto which the MCCH is mapped. More specifically, each mobileterminal determines the SFN number of the leading one of system framesonto which the MCCH is mapped by using the MCCH repetition period lengthand the starting point value which are an example of the parameterswhich the mobile terminal receives in step ST1725, and determineswhether or not it is the leading one of system frames onto which theMCCH is mapped on the basis of an SFN mapped onto the BCCH or the liketo determine whether it is the SFN number of the leading one of systemframes onto which the MCCH is mapped. When the current time is not theone of the leading one of system frames onto which the MCCH is mapped,each mobile terminal makes a transition to step ST1753. In contrast,when the current time is the one of the leading one of system framesonto which the MCCH is mapped, each mobile terminal makes a transitionto step ST1788. Furthermore, in a case of FIG. 26, the determination ofstep ST1772 can be carried out every MCCH repetition period 1.Furthermore, for example, in a case of FIG. 27 or 29, the determinationcan be carried out every MCCH repetition period. When the current timeis the SFN number of the paging occasion in ST6301, each mobile terminalmakes a transition to ST6302.

Paging to the mobile terminal in question occurs in step ST6307. An MMEin which paging has occurred, in step ST6308, checks the TA (TrackingArea) list of the mobile terminal in question on the basis of anidentifier (UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal forwhich the paging is destined. The MME, in step ST6309, determineswhether or not a TA(MBMS) is included in the TA list of the mobileterminal in question. As a concrete example, the MME searches throughthe tracking area list of the mobile terminal in question, such as alist as shown in FIG. 31[a], on the basis of the UE-ID. In a case inwhich the mobile terminal in question is the UE#1 (UE-ID#1) of FIG.31[a], the MME determines that the TA(MBMS) is not included in thetracking area list. In contrast, in a case in which the mobile terminalin question is the UE#2 (UE-ID#2) of FIG. 31[a], the MME determines thatthe TA(MBMS) is included is the tracking area list because the TA(MBMS)#1 is included in the list. When the TA(MBMS) is not included in thetracking area list, the MME makes a transition to step ST1814. Incontrast, when the TA(MBMS) is included in the tracking area list, theMME makes a transition to step ST6310. The MME, in step ST6310,transmits a paging request (Paging Request) to MCEs. As the MCEs towhich the MME transmits a paging request, there can be considered allMCEs each of which manages base stations which geographically overlapthe base stations managed by the MME. As an example of parametersincluded in the paging request, there can be considered an identifier(UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal, the TA(MBMS)number, and so on. At this time, instead of the TA(MBMS) number, eitherf(MBMS) and MBSFN area IDs or only MBSFN area IDs can be provided.

Each of the MCEs, in step ST6311, receives the paging request. Among theMCEs each of which receives the paging request in step ST6312, an MCEwhich controls the MBSFN area ID related to the TA(MBMS) number informedthereto as a parameter included in the paging request makes preparationsfor paging transmission. As an example of the preparations for pagingtransmission, the MCE which controls the MBSFN area ID determines thepaging group and the paging occasion (paging occasion) of the mobileterminal in question by using the parameters for the time ofdiscontinuous reception at the time of MBMS reception. Concretely, theparameters for the time of discontinuous reception at the time of MBMSreception are the number Ksf of paging groups of the self-base station(the MBSFN area to which the base stations belong), the discontinuousreception cycle lengths in the frequency layer dedicated to MBMStransmission, a, k, the DRX information, etc. When determining thepaging group and the paging occasion, the same computation expression asthat used by the mobile terminal side is used. Because the concretecomputation expression for determining the paging group and the pagingoccasion is mentioned above, the explanation of the concrete computationexpression will be omitted hereafter. As mentioned above, in accordancewith the method of managing a correspondence between TA(MBMS) numbers(MBSFN Areas) and MCEs which is carried out by an MCE which receives apaging request, because a relation between an MBSFN area ID and an MCEwhich controls the MBSFN area can be provided only within thearchitecture of MBMS services, that is, because the relation can beprovided regardless of the MME, there can be provided an advantage ofbecoming able to make the mobile communication system have a high degreeof flexibility.

Furthermore, there is considered a case in which the MME manages theMBSFN area ID related to the TA(MBMS) number as shown in FIG. 31[c], andalso manages the MBSFN area ID and the number of an MCE which controlsthe MBSFN area as shown in FIG. 31[d]. In this case, the MME, in stepST6310, transmits the paging request only to an MCE which manages theMBSFN area ID related to the TA(MBMS) number. As an example of theparameter included in the paging request at that time, there can beconsidered an identifier of the mobile terminal, or the like. The MCEwhich receives the paging request in step ST6311 makes preparations forpaging transmission, like in the above-mentioned case. As mentionedabove, because the method (FIG. 31[d]) of managing the relation betweenan MBSFN area ID and an MCE which controls the MBSFN area in the MMEreduces the number of MCEs to which the paging request is transmittedfrom the MME, there is provided an advantage of being able to makeeffective use of the resources. Furthermore, because the amount ofinformation to be transmitted decreases, there is provided an advantageof being able to make effective use of the resources.

Furthermore, there is considered a case in which the MME manages theMBSFN area ID related to the TA(MBMS) number as shown in FIG. 31[c], andalso manages the MBSFN area ID and the cell IDs of an MBMS dedicatedcell and an MBMS/Unicast-mixed cell which are included in the MBSFN areaID as shown in FIG. 31[e]. In this case, the MME, in step ST6310,transmits the paging request to the cells whose IDs are included in theMBSFN area ID which is managed not by an MCE but by the MME. As anexample of the parameter included in the paging request at that time,there can be considered an identifier of the mobile terminal, or thelike. As mentioned above, the method of managing the relation between anMBSFN area ID and cells whose IDs area included in the MBSFN area ID inthe MME (FIG. 31 [e]) eliminates the necessity for an MCE to carry outprocesses regarding the transmission of a paging signal to the mobileterminal. Because this results in elimination of the necessity to addany function to each MCE, there can be provided an advantage of beingable to avoid the complexity of each MCE. Furthermore, there can beprovided an advantage of being able to reduce the processing load oneach MCE.

Actually, the channel structure of a paging dedicated channel (DPCH)disclosed in Embodiment 8 and the method of mapping a paging signal ontothe paging signal dedicated channel can be applied to an example of thestructure of a channel onto which a paging signal in the frequency layerdedicated to MBMS transmission is mapped. The configuration and themethod are shown in FIGS. 43, 44, and 45. Because the detailedexplanation of the configuration and the method is disclosed inEmbodiment 8, the explanation will be omitted hereafter.

Hereafter, the structure of a channel onto which a paging signal in afrequency layer dedicated to MBMS transmission is mapped will beexplained with reference to an example shown in FIGS. 43 and 44. An MCE,in step ST6313, carries out scheduling of a paging signal destined for amobile terminal in question. More specifically, the MCE determines thevalue of a PCFICH from the physical area for paging signal (the numberof OFDM symbols) which is required according to the number of mobileterminals for each of which paging is occurring. Furthermore, the MCEdetermines to the how-manyth one of information elements mapped onto thephysical area for paging signal on the MBSFN subframe number of thesystem frame of the SFN number acquired from the paging group number andthe paging occasion of the mobile terminal in question determined instep ST6312 an identifier of the mobile terminal in question isallocated. By making the MCE carry out this scheduling, an identifier ofthe mobile terminal in question is transmitted from the same physicalresources of base stations included in the MBSFN area. As a result,there can be provided an advantage of enabling each mobile terminal toreceive a paging signal benefiting from an SFN gain by receiving theDPCH which is transmitted via a multi-cell transmission scheme in theMBSFN area. The MCE, in step ST6314, transmits a paging request for themobile terminal in question to the base stations in the MBSFN area. Asan example of parameters included in the paging request, an identifier(UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal, the result ofthe scheduling of the paging signal carried out in step ST6313(concretely, an SFN, an MBSFN subframe number, an information elementnumber, and a PCFICH value), etc. can be considered. Each of the basestations in the MBSFN area, in step ST6315, receives the paging requestfrom the MCE.

Instead of disposing only an IF between MME and MCE between the MME 103and the MCE 801, an MME-MBMS GW interface can also be disposed betweenthe MME 103 and an MBMS GW 802 (in more detail, an MBMS CP 802-1).Furthermore, the processes of steps ST6311 to ST6314, which are carriedout by the MCE, can be carried out by the MBMS GW on behalf of the MCE.In this variant, the same advantages as those provided by the presentinvention are provided.

Each of the base stations in the MBSFN area, in step ST6316, determinesthe paging group and paging occasion of the mobile terminal in question.When determining them, each of the base stations uses the samecomputation expression as that used by the mobile terminal side. Whenthe paging group and paging occasion of the mobile terminal in questionare also informed in step ST6314, step ST6316 can be eliminated. As aresult, there can be provided an advantage of reducing the control loadon each base station in the MBSFN area. In contrast, in accordance withthe method of, in step ST6316, determining the paging group and pagingoccasion in each base station in the MBSFN area without informing thepaging group or paging occasion of the mobile terminal in question instep ST6314, there can be provided an advantage of being able to reducethe amount of information notified from the MCE to each base station inthe MBSFN area, and making effective use of the resources. Each basestation in the MBSFN area, in step ST6317, derives the radio framenumber and the MBSFN subframe numbers via which to transmit the pagingsignal by using the identifier of the mobile terminal in questionreceived in step ST6315, the result of the scheduling of the pagingsignal, etc. Each base station, in step ST6318, maps the PCFICH valueonto the physical area of the PCFICH having the derived radio framenumber and the derived MBSFN subframe numbers, and allocates theidentifier of the mobile terminal in question to the information elementnumber to map the identifier onto the physical area of the DPCH of thederived radio frame number and the derived MBSFN subframe numbers andtransmit the identifier. The paging signal is transmitted to each basestation in the MBSFN area. As the mapping method of mapping theidentifier onto the paging-related area in the DPCH and the mappingmethod of mapping the identifier onto the concrete physical channel,etc. which are used at that time, the methods disclosed in Embodiment 8can be used.

The mobile terminal, in step ST6302, receives the PCFICH in the MBSFNsubframes of the group to which the mobile terminal belongs and whichare acquired from the result of the determination of the paging group.The mobile terminal, in step ST6303, determines the number of OFDMsymbols for the DPCH from the PCFICH. The mobile terminal, in stepST6304, receives and decodes the physical area onto which the DPCH inthe same MBSFN subframes is mapped on the basis of the determined numberof OFDM symbols for the DPCH. At that time, the mobile terminal carriesout blind detection by carrying out an operation of calculating acorrelation with the mobile-terminal-specific identification code. Themobile terminal, in step ST6305, determines whether it has detected theidentifier of the mobile terminal itself through the blind detectioncarried out in step ST6304. When the mobile terminal has not detectedthe identifier of the mobile terminal itself, the mobile terminal makesa transition to step ST1788. In contrast, when the mobile terminal hasdetected the identifier of the mobile terminal itself, the mobileterminal makes a transition to step ST1819.

As a result, there can be disclosed a method of transmitting a pagingsignal to a mobile terminal currently receiving an MBMS service in afrequency layer dedicated to MBMS transmission, and a mobilecommunication system which enables the method to be implemented therein,which are a challenge of the present invention. Therefore, there isprovided an advantage of enabling even a mobile terminal currentlyreceiving an MBMS service in the frequency layer dedicated to MBMStransmission to receive a paging signal.

By using the method of transmitting a paging signal in a frequency layerdedicated to MBMS transmission, which is disclosed in this embodiment,the number of MBSFN subframes onto which a paging signal is mapped, andthe number of radio frames having the MBSFN subframes can be increased.Therefore, it becomes able to reduce the number of mobile terminalswhich are mapped onto one MBSFN subframe, and therefore the physicalarea required to carry paging signals whose number is equal to thenumber of mobile terminals onto one MBSFN subframe can be reduced.Furthermore, because it is not necessary to determine the discontinuousreception cycle length in the MBMS transmission frequency layerdepending on the length of each of the periods at which the MCCH istransmitted, the system becomes able to set up the discontinuousreception cycle length with flexibility.

As the method of transmitting a paging signal, the one in the case inwhich a paging occasion exists in each of all the radio frames excludingradio frames corresponding to the DRX periods is described above. As analternative, a paging occasion can exist in one or more of all the radioframes excluding radio frames corresponding to the DRX periods. As aresult, there is no necessity to provide a paging dedicated channel(DPCH) for carrying a paging signal in all the radio frames, it becomesable to transmit data for MBMS service via a radio frame onto which anypaging signal is not mapped, and MBMS services can be speeded up and canincrease in volume. A concrete method of allowing a paging occasion toexist in one or more of all the radio frames excluding radio framescorresponding to the DRX periods will be disclosed. A computationexpression for determining the paging group is similarly given by IMSImod K, where K is the number of paging groups.

A concrete example of the value of K is the number of MBSFN subframes inone radio frame. For example, in a case in which the number of MBSFNsubframes in one radio frame is 10, K is equal to 10. In contrast, in acase in which the value of K is the number of MBSFN subframes in oneradio frame excluding MBSFN subframes #0 and #5 onto which an SCH ismapped, K is equal to 8. By bringing the value of K (a remainder valueat K) into correspondence with subframe numbers in one radio frame, eachmobile terminal is enabled to know onto which subframe in one radioframe the paging information about the group to which the mobileterminal itself belongs is mapped from the value of the paging groupdetermined according to the above-mentioned equation. Next, acorrespondence about onto which radio frame the paging signal destinedfor the group to which the mobile terminal itself belongs is mapped isestablished. A concrete example of a computation expression fordetermining the radio frame is given as follows. First, a case in whichthere is no DRX period will be disclosed.

“Paging occurrence radio frame” (Paging Occasion)=(IMSI or K) modX+n×(the discontinuous reception cycle length in the MBMS transmissionfrequency layer), where n: 0, 1, 2, or . . . , and Paging Occasion≦themaximum of SFN. SFN is an integer ranging from 0 to the maximum of SFN.X is the number of radio frames in each of which paging has occurredwithin a discontinuous reception cycle in the MBMS transmissionfrequency layer, and satisfies the following inequality: X≦thediscontinuous reception cycle length (a number of radio frames) in theMBMS transmission frequency layer. The value of X (a remainder value atX) is associated with a radio frame number (SFN).

When the paging occurrence radio frame is determined in this way, pagingcan be made to occur in each of the X radio frames within adiscontinuous reception cycle in the MBMS transmission frequency layer,and the value of the paging occasion determined according to theabove-mentioned equation shows onto which radio frame the paginginformation destined for the mobile terminal itself is mapped. No pagingoccasion occurs in radio frames other than the radio frames associatedwith the value of X, and data for the MBMS service can be transmittedvia the radio frames. In a case in which a radio frame in which pagingoccurs is periodic, the paging occurrence radio frame can be given bythe following equation when, for example, the cycle length is TX.

“Paging occurrence radio frame” (Paging Occasion)=((IMSI div K) mod(Int(T/TX)))×TX+n×(the discontinuous reception cycle length in the MBMStransmission frequency layer), where n: 0, 1, 2, or . . . , and PagingOccasion≦the maximum of SFN. SFN is an integer ranging from 0 to themaximum of SFN. TX satisfies the following inequality: TX≦thediscontinuous reception cycle length (a number of radio frames) in theMBMS transmission frequency layer.

Because it becomes unnecessary to associate the above-mentioned value ofX (the remainder value at X) with the radio frame number (SFN) by makinga radio frame in which paging occurs periodic, the equation fordetermining the paging occasion can be simplified. Next, a case in whichthere is a DRX period will be disclosed.

“Paging occurrence radio frame” (Paging Occasion)=(IMSI div K)modX+n×(the discontinuous reception cycle length in the MBMS transmissionfrequency layer), where n: 0, 1, 2, or . . . , and Paging Occasion≦themaximum of SFN. SFN is an integer ranging from 0 to the maximum of SFN.X is the number of radio frames in each of which paging occurs within adiscontinuous reception cycle in the MBMS transmission frequency layer,and satisfies the following inequality: X≦(SFNmax-ΣDRX). The value of X(a remainder value of X) is associated with a radio frame number (SFN).

As an alternative, “paging occurrence radio frame” (PagingOccasion)=(IMSI div K) mod (Int(T/TX)))×TX+n×(the discontinuousreception cycle length in the MBMS transmission frequency layer), wheren: 0, 1, 2, or . . . , and Paging Occasion≦the maximum of SFN. SFN is aninteger ranging from 0 to the maximum of SFN. TX≦(SFNmax-ΣDRX). Thepaging occasion has a value which is obtained by renumbering the radioframes except those corresponding to the DRX periods.

Required ones of the above-mentioned parameters for the time ofdiscontinuous reception at the time of MBMS reception have only to beinformed according to the used computation expression for determiningthe paging group and paging occasion (paging occasion). For example, inthe above-mentioned computation expression for determining the pagingoccasion, the parameters for the time of discontinuous reception at thetime of MBMS reception include the discontinuous reception cycle lengthin the frequency layer dedicated to MBMS transmission, X, thecorrespondence between the value of X (the remainder value of X) and aradio frame number (SFN), TX, K, and the correspondence between thevalue of K (the remainder value of K) and a subframe. These parametersfor the time of discontinuous reception at the time of MBMS reception,as well as the information about the scheduling of the MCCH, can beinformed to the mobile terminal by using the BCCH from the MBMSdedicated cell in steps ST1723 and ST1724. Furthermore, the parametersfor the time of discontinuous reception at the time of MBMS reception,as well as the MBMS area information, the DRX information formeasurement in the unicast/mixed frequency layer, and the number ofpaging groups, can be informed to the mobile terminal by using the MCCHfrom the MBMS dedicated cell in steps ST1728 and ST1729. In this case,although the parameters required for the computation expression fordetermining the paging occasion have only to be informed, a parametershowing at which time (SFN) should be received when the mobile terminalperforms a discontinuous reception operation can be used instead of theparameters required for the equation for determining the pagingoccasion. As a concrete example, an explicit receiving timing (SFN) anda discontinuous reception cycle length can be provided. Instead ofincluding the correspondence between the value of X (the remainder valueof X) and a radio frame number (SFN), and the correspondence between thevalue of K (the remainder value of K) and a subframe into theparameters, they can be predetermined. For example, in a casein whichthe number of subframes onto which the paging signal is mapped isexpressed as K, the case in which the remainder value of K is 0 isassociated with the first one of the subframes in one radio frame ontowhich the paging signal is mapped, the case in which the remainder valueof K is 1 is associated with the second one of the subframes in oneradio frame onto which the paging signal is mapped, . . . , and the casein which the remainder value of K is K−1 is associated with the K-th oneof the subframes in one radio frame onto which the paging signal ismapped. By defining the correspondence between the value of K and asubframe in this way, the amount of signaling can be reduced and thecapacity of transmission of MBMS services can be increased.

As the paging signal transmitting method, the method of allowing apaging occasion to exist in one or more of all the radio framesexcluding radio frames corresponding to the DRX periods is shown above.This method can also be applied to a case in which MBSFN subframescorresponding to an MBSFN area is TDM-multiplexed. As previouslymentioned, in the case in which MBSFN subframes corresponding to anMBSFN area is TDM-multiplexed, instead of (SFNmax-ΣDRX), the number ofradio frames each having MBSFN subframes corresponding to theabove-mentioned MBSFN area can be provided.

As mentioned above, the method of providing a physical channel dedicatedto paging (DPCH), as disclosed in Embodiment 8, which is transmitted viaa multi-cell transmission scheme in an MBSFN area, and carrying a pagingsignal onto this physical channel can be applied to a physical area ontowhich the paging signal is mapped. In this case, the DPCH does not haveto be formed in all the radio frames corresponding to the MBSFN area,and has only to be formed in a radio frame in which a paging occasionoccurs. As an alternative, the DPCH can be formed in all the MBSFNsubframes in a radio frame, or can be formed in K MBSFN subframes in aradio frame. As a result, because it becomes able to transmit data forMBMS service via a radio frame in which the DPCH is not formed, MBMSservices can be speeded up and can increase in volume. By thus providingthe method of transmitting a paging signal, there is provided anadvantage of being able to, even in a case in which a DRX period isprovided in a frequency layer dedicated to MBMS transmission of an LTEsystem, enable an MBMS dedicated cell to transmit a paging signal in thefrequency layer dedicated to MBMS transmission. In the paging method inaccordance with the present invention, because communications arecarried out by a unicast cell after paging, only a paging indicator(Paging Indicator: PI) informing the presence or absence of an incomingcall can be transmitted as the paging information to be transmitted by abase station. Also in this case, the configuration of the DPCH disclosedin Embodiment 8 can be applied.

Embodiment 16

In Embodiment 2, the method of transmitting a paging signal from allcells in an MBSFN area transmitting an MBMS service which a mobileterminal is receiving or trying to receive is disclosed. In thisembodiment, in order to enable a mobile terminal to receive a pagingsignal in a frequency layer dedicated to MBMS irrespective of whether anMBSFN area covering a plurality of MBSFN areas exists, a method oftransmitting a paging signal from all cells in an MBSFN synchronizationarea (MBSFN Synchronization Area) by using a main PMCH will bedisclosed. An explanation will be made focusing on a portion differentfrom Embodiment 2. Portions which will not be explained specifically arethe same as those explained in Embodiment 2.

As a physical channel onto which a paging signal is mapped, a main PMCHused for multi-cell transmission in all cells in an MBSFNsynchronization area is used. A description about the main PMCH is madein Embodiment 9. The main PMCH is configured in such a way thatsynchronization is established in all the cells in the MBSFNsynchronization area, and is subjected to SFN combining. One MBSFN areato which all the cells in the MBSFN synchronization area belong can beprovided, and MBSFN subframes corresponding to this MBSFN area can beprovided as the main PMCH. In this embodiment, a case in which timedivision multiplexing and code division multiplexing coexist for a PMCHprovided for each MBSFN area will be explained as an example. Theconfiguration of the physical channel (i.e., the main PMCH) which istransmitted via a multi-cell transmission scheme in the MBSFNsynchronization area (MBSFN Synchronization area) is shown in FIG. 46. Acell #n1 is one located in an MBSFN area 1, a cell #n2 is one located inan MBSFN area 2, and a cell #n3 is one located in an MBSFN area 3.Furthermore, the cells #1, #2, and #3 also belong to an MBSFN area 4.The main PMCH is provided while being time-division-multiplexed withMBSFN subframes for other MBSFN areas, and is transmitted at a main PMCHrepetition period. Because a concrete configuration of the main PMCH isdisclosed in Embodiment 9, the explanation of the concrete configurationwill be omitted.

A flow of the processing carried out by the mobile communication systemdescribed in this embodiment will be explained. Because a paging signalis mapped onto the main PMCH which is transmitted via a multi-celltransmission scheme in all the cells in the MBSFN synchronization area,the method of transmitting a paging signal to a mobile terminal differsfrom that shown in Embodiment 2. The portion different from the methoddisclosed in Embodiment 2 will be mainly shown. First, in addition toinformation about the scheduling of an MCCH, such as an MCCH repetitionperiod length, information about the scheduling of the main PMCH has tobe transmitted to each mobile terminal. Concretely, as the informationabout the scheduling of the main PMCH, the start timing of the main PMCH(an SFN and a starting point), a main PMCH repetition period length, asubframe number, a paging signal presence or absence indicatorrepetition period length, an MBMS-related modified or unmodifiedindicator repetition period length, the start timings (SFNs and startingpoints) of MBSFN subframes in which these indicators exist, subframenumbers, and so on are provided. The information about the scheduling ofthe main PMCH, as well as the information about the scheduling of theMCCH, can be transmitted from a MBMS dedicated cell to each mobileterminal by using a BCCH in steps ST1723 and ST1724. As an alternative,the information about the scheduling of the main PMCH, as well as MBMSarea information, DRX information for measurement in a unicast/mixedfrequency layer, and the number of paging groups, can be informed froman MBMS dedicated cell to each mobile terminal by using the MCCH insteps ST1728 and ST1729.

Because an MCH and a PCH mapped onto the main PMCH and a scrambling codeused in the main PCH are transmitted via a multi-cell transmissionscheme in the MBSFN synchronization area, the scrambling code differsfrom that corresponding to an MBSFN area (e.g., an MBSFN area 1) towhich the MBMS dedicated cell which has made a search belongs.Therefore, this scrambling code also needs to be informed to each mobileterminal. This scrambling code, as well as the information about thescheduling of the main PMCH, can be informed from the MBMS dedicatedcell to each mobile terminal by using the BCCH in steps ST1723 andST1724. As an alternative, the scrambling code can be informed from theMBMS dedicated cell to each mobile terminal by using the MCCH in stepsST1728 and ST1729. Each mobile terminal receives the main PMCH on thebasis of the main PMCH scheduling information received in step ST1724 orST1729, and becomes able to descramble (descramble) the main PMCH byusing this scrambling code received in step ST1724 or ST1729 to decode(decode) the main PMCH. Because this scrambling code is used in all thecells in the MBSFN synchronization area, it can be predetermined or canbe transmitted from a serving cell to each mobile terminal together witha receivable f(MBMS) within the self-cell in the broadcasting of areceivable MBMS in steps ST1707 and ST1708. The number K of paginggroups (referred to as Kmp) which is explained in Embodiment 9 and whichis used in the channel structure of the main PMCH is transmitted, insteps ST1728 and ST1729, from the MBMS dedicated cell to each mobileterminal while being included in the MCCH of an MBSFN area (e.g., theMBSFN area 1) to which the MBMS dedicated cell which has made a searchbelongs, like in the case of Embodiment 2. Each mobile terminal, in stepST1735, determines a paging group, as discontinuous receptionpreparations at the time of MBMS reception, by using this number Kmp ofpaging groups.

Next, a tracking area (TA) list at a frequency dedicated to MBMStransmission will be explained. Because the main PMCH is transmitted viaa multi-cell transmission scheme in all the cells in the MBSFNsynchronization area, all of the MBSFN synchronization area can be madeto be a range of transmission of a paging signal to each mobileterminal. Therefore, the tracking area of the MBMS transmissiondedicated cell can be made to be all of the MBSFN synchronization area.In Embodiment 2, a TA list of each mobile terminal is shown in FIG.31[a], and a table showing a correspondence between a TA(unicast) in theunicast/mixed frequency layer and cells belonging is shown in FIG.31[b]. These TA list and table can be applied also to this embodiment.Next, in this embodiment, a table for associating a tracking area (TA)at a frequency dedicated to MBMS transmission with an MBSFNsynchronization area is newly provided. A concrete example of tablesshowing a tracking area (TA) at a frequency dedicated to MBMStransmission is shown in FIG. 78. A table showing MBSFN area IDs and anf(MBMS) number, and an MBSFN synchronization area number (ID) to whichthey belong is shown in FIG. 78[a]. By using this table, an MBSFNsynchronization area number is associated with MBSFN area IDs and anf(MBMS) number. A table showing a relation between an MBSFNsynchronization area ID and a TA(MBMS) number is shown in FIG. 78[b]. Byusing this table, a TA(MBMS) number in the frequency layer dedicated toMBMS to which an MBSFN area from which a mobile terminal is receivingbelongs is associated with an MBSFN synchronization area ID.

The details of management of a TA list will be explained. The method inthe receiving state on the side of MBMS, which is disclosed inEmbodiment 2, can be applied. As shown in FIG. 20, a mobile terminal, instep ST1742, transmits a “notification of the MBMS side receiving state”to a serving cell according to UL (Uplink) allocation received in stepST1741. As an example of parameters included in the “notification of theMBMS side receiving state”, an identifier (UE-ID, IMSI, S-TMSI, or thelike) of the mobile terminal, a frequency (f(MBMS)) at which the mobileterminal receives an MBMS service, and an MBSFN area number (ID) areincluded. The serving cell, in step ST1743, receives the MBMS sidereceiving state notification from the mobile terminal. The network side,in step ST1743, can know that the mobile terminal in question isreceiving the MBMS service in the frequency layer dedicated to MBMStransmission without adding any uplink channel to the MBMS dedicatedcell, i.e., without increasing the complexity of the mobilecommunication system. As a result, there is provided an advantage ofenabling the general configuration in which the network side informspaging signals to be changed into the configuration of carrying outdiscontinuous reception at the time of MBMS reception. The serving cell,in step ST1744, transmits the MBMS side receiving state notification toan MME. The MME, in step ST1745, receives the MBMS side receiving statenotification from the serving cell. The MME, in step ST1746, determinesa tracking area (referred to as a TA(MBMS) from here on) in which themobile terminal in question is receiving the MBMS service at thefrequency dedicated to MBMS transmission. The MME determines thetracking area on the basis of the notification of the MBMS sidereceiving state, more specifically, the parameters of the MBMS sidereceiving state, more concretely, f(MBMS) and the MBSFN area numberincluded in the parameters.

In a case in which there is a point-to-point correspondence betweenf(MBMS) and an MBSFN synchronization area, it is not necessary to useany MBSFN area number. Concretely, MBSFN area IDs are excluded from thetable of FIG. 78[a]. Furthermore, no MBSFN area number is included inthe parameters about the MBMS side receiving state in steps ST1742 toST1745. By configuring the table and the parameters in this way, itbecomes able to reduce the amount of signaling between each mobileterminal and each serving cell, between serving cells, and between MMES,and the efficiency of the radio resources can be improved.

The MME, in step ST1747, updates the tracking area lists of the mobileterminals in question. In the current 3GPP, it has been decided that aplurality of tracking areas (each referred to as a TA(unicast) from hereon) is provided for each mobile terminal in a unicast/mixed frequencylayer. However, in the current stage in which it has not decided whetherto transmit a paging signal destined for a mobile terminal from an MBMSdedicated cell or in a frequency layer dedicated to MBMS transmission,an MBMS dedicated cell and a frequency layer dedicated to MBMStransmission as to a plurality of tracking areas are not taken intoconsideration. The MME, in step ST1747, carries out management (storage,addition, update, and deletion) of the TA list including a TA(unicast)and/or a TA(MBMS). The details of the management of the TA list of stepST1747 will be explained. The MME searches for the TA(MBMS) number whichis managed within the MME on the basis of f(MBMS) and the MBSFN area IDswhich the MME receives in step ST1745. In a concrete searching method,the tables as shown in FIG. 78 are used. The MME searches for thecorresponding MBSFN synchronization area number (ID) by using FIG. 78[a]from f(MBMS) and the MBSFN area IDs received thereby, and furthersearches for the corresponding TA(MBMS) number by using FIG. 78 [b].Next, the MME determines whether the TA(MBMS) which has been searchedfor as the result of the search exists in the TA list of the mobileterminal in question.

When the TA(MBMS) exists in the TA list, the MME stores the current TAlist. In contrast, when the TA(MBMS) does not exist in the TA list, theMME adds the above-mentioned TA(MBMS) to the TA list of mobile terminalin question. The MME, in step ST1748, transmits a response signal Ackshowing that the MME has received the notification of the MBMS sidereceiving state to the serving cell. As an example of the parameterincluded in Ack showing that the MME has received the notification ofthe MBMS side receiving state, the TA list of the mobile terminal inquestion can be considered. The serving cell, in step ST1749, receivesthe Ack to the notification of the MBMS side receiving state from theMME. The serving cell, in step ST1750, transmits the Ack to thenotification of the MBMS side receiving state to the mobile terminal.The mobile terminal, in step ST1751, receives the Ack to thenotification of the MBMS side receiving state from the serving cell. Themobile terminal, in step ST1752, moves to the frequency layer dedicatedto MBMS transmission by changing the frequency set to the frequencyconverting unit 1107 thereof to change the center frequency to thefrequency (f(MBMS)) in the frequency layer dedicated to MBMStransmission.

Next, the details of a process at a time when paging for the mobileterminal in question occurs in this embodiment will be explained. Pagingfor the mobile terminal in question occurs in step ST1773. The MME inwhich paging has occurred, in step ST1774, checks to see the TA list ofthe mobile terminal in question on the basis of an identifier (UE-ID,IMSI, S-TMSI, or the like) of the mobile terminal in question for whichthe paging is destined. The MME, in step ST1775, determines whether ornot the TA(MBMS) is included in the TA list of the mobile terminal inquestion. As a concrete example, the MME searches through the TA list ofthe mobile terminal in question, such a list as shown in FIG. 31[a], onthe basis of UE-ID. In a case in which the mobile terminal in questionis the UE#1 (UE-ID#1) of FIG. 31[a], the MME determines that theTA(MBMS) is not included is the tracking area list. In contrast, in acase in which the mobile terminal in question is the UE#2 (UE-ID#2) ofFIG. 31[a], the MME determines that the TA(MBMS) is included is thetracking area list because the TA(MBMS)#1 is included in the list. Whenthe TA(MBMS) is not included in the tracking area list, the MME makes atransition to step ST1814. In contrast, when the TA(MBMS) is included inthe tracking area list, the MME makes a transition to step ST1776. TheMME, in step ST1776, transmits a paging request to MCEs. As the MCEs towhich the MME transmits a paging request, there can be considered allMCEs each of which manages base stations which geographically overlapthe base stations managed by the MME. As an example of parametersincluded in the paging request, there can be considered an identifier(UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal, the TA(MBMS)number, and so on. At this time, instead of the TA(MBMS) number, eitherboth f(MBMS) and MBSFN area IDs or an MBSFN synchronization area ID canbe provided.

Each of the MCEs, in step ST1777, receives the paging request. Among theMCEs each of which receives the paging request in step ST1778, an MCEwhich controls either the MBSFN synchronization area ID or both f(MBMS)and the MBSFN area IDs which are informed thereto as a parameterincluded in the paging request and which are related to the TA(MBMS)number makes preparations for paging transmission. As an example of thepreparations for paging transmission, an MCE which controls either theMBSFN synchronization area ID or both f(MBMS) and the MBSFN area IDsdetermines the paging group of the mobile terminal in question by usingboth the number Kmp of paging groups used for the main PMCH and thereceived paging request. When determining the paging group, the MCE usesthe same computation expression as that used by the mobile terminal. Asa concrete example, the MCE uses the same equation as that in stepST1735, i.e., paging group=IMSI mod Kmp. As mentioned above, because theMCE which has received the paging request has the information, as shownin, for example, the table of FIG. 78, for bringing a TA(MBMS) numberinto correspondence with an MCE, and the method of managing thecorrespondence can provide a relation between an MBSFN synchronizationarea ID or both f(MBMS) and MBSFN area IDs, and an MCE which controlsthem only within the architecture of MBMS services, that is, because therelation can be provided regardless of the MME, there can be provided anadvantage of becoming able to make the mobile communication system havea high degree of flexibility.

Furthermore, there is considered a case in which the MME manages f(MBMS)and the MBSFN area IDs related to the TA(MBMS) number as shown in FIG.78, and also manages f(MBMS) and the MBSFN area IDs and the number of anMCE which controls them as shown in FIG. 79[a]. In this case, the MME,in step ST1776, transmits the paging request only to an MCE whichmanages f(MBMS) and the MBSFN area IDs related to the TA(MBMS) number.As an example of a parameter included in the paging request at thattime, there can be considered an identifier of the mobile terminal, orthe like. Although the table showing the correspondence between f(MBMS)and MBSFN area IDs, and an MCE that controls them is shown in FIG.79[a], a table showing a correspondence between an MBSFN synchronizationarea ID, instead of f(MBMS) and MBSFN area IDs, and the number of an MCEwhich controls it can be used. The MCE which receives the paging requestin step ST1778 makes preparations for paging transmission, like in theabove-mentioned case. As mentioned above, because the method of managingthe relation between both f(MBMS) and MBSFN area IDs, and an MCE whichcontrols them in the MME reduces the number of MCEs to which the pagingrequest is transmitted from the MME, there is provided an advantage ofbeing able to make effective use of the resources. Furthermore, becausethe amount of information to be transmitted decreases, there is providedan advantage of being able to make effective use of the resources.

Furthermore, there is considered a case in which the MME manages bothf(MBMS) and MBSFN area IDs related to a TA(MBMS) number as shown in FIG.78, and also manages both f(MBMS) and an MBSFN area ID, and the cell IDsof an MBMS dedicated cell and/or a mixed cell which is included in theMBSFN area ID as shown in FIG. 79[b]. In this case, the MME, in stepST1776, transmits the paging request to the cells whose IDs are includedin MBSFN area ID which is not managed by an MCE but by the MME. As anexample of a parameter included in the paging request at that time,there can be considered an identifier of the mobile terminal, or thelike. Also in this case, a table showing a correspondence between anMBSFN synchronization area ID, instead of f(MBMS) and an MBSFN area ID,and the cell IDs of an MBMS dedicated cell and/or a mixed cell includedin the MBSFN synchronization area can be provided instead of the tableas shown in FIG. 79[b], like in the case of FIG. 79[a]. As mentionedabove, the method of managing the relation between f(MBMS) and an MBSFNarea ID, and cells whose IDs area included in the MBSFN area ID in theMME eliminates the necessity for an MCE to carry out processes regardingthe transmission of a paging signal to the mobile terminal. Because thisresults in elimination of the necessity to add any function to each MCE,there can be provided an advantage of being able to avoid the complexityof each MCE. Furthermore, there can be provided an advantage of beingable to reduce the processing load on each MCE. Because the methoddisclosed in Embodiment 9 can be applied to the structure of a channelonto which a paging signal in the frequency layer dedicated to MBMStransmission is mapped, the explanation of the method will be omittedhereafter.

An MCE, in step ST1779, carries out scheduling of a paging signaldestined for a mobile terminal in question. More specifically, the MCEdetermines to the how-manyth one of information elements mapped onto thephysical area allocated to the number of the paging group of the mobileterminal in question determined in step ST1778 an identifier of themobile terminal in question is allocated. In this case, the physicalarea onto which the paging signal is mapped is the one for the main PMCHwhich is transmitted via a multi-cell transmission scheme in the MBSFNsynchronization area, unlike in the case of using the method disclosedin Embodiment 2. By making the MCE which controls either the MBSFNsynchronization area ID or both f(MBMS) and the MBSFN area IDs, whichare related to the TA(MBMS) received in ST1777 carry out thisscheduling, an identifier of the mobile terminal in question istransmitted from the same physical resources of base stations includedin the MBSFN synchronization area. As a result, there can be provided anadvantage of enabling each mobile terminal to receive a paging signalbenefiting from an SFN gain by receiving the PMCH which is transmittedvia a multi-cell transmission scheme in the MBSFN synchronization area.The MCE, in step ST1780, transmits a paging request for the mobileterminal in question to the base stations in the MBSFN area. As anexample of parameters included in the paging request, an identifier(UE-ID, IMSI, S-TMSI, or the like) of the mobile terminal, the result ofthe scheduling of the paging signal carried out in step ST1779(concretely, the SFN of the main PMCH, an MBSFN subframe number, and aninformation element number), etc. can be considered. Each of the basestations in the MBSFN area, in step ST1781, receives the paging requestfrom the MCE.

In the scheduling of the paging signal destined for the mobile terminal,the paging signal can be mapped onto all the subframes via which themain PMCH is transmitted, or can be mapped onto some of the subframesvia which the main PMCH is transmitted. For example, the paging signalcan be mapped onto subframes onto which an MCCH or a main MCCH is mappedin the main PMCH. In the case in which the paging signal is mapped ontosome of the subframes via which the main PMCH is transmitted, thesubframes can be predetermined or can be broadcast from a unicast/mixedcell or an MBMS dedicated cell. As an alternative, the subframes can bederived by the network side (an MME and an MCE), the base station, andeach mobile terminal by using an identical computation expression andidentical parameters. These parameters and this computation expressioncan be predetermined, or can be broadcast from a unicast/mixed cell oran MBMS dedicated cell. By carrying the paging signal on all thesubframes, paging to many mobile terminals can be carried out with ashorter delay time. In contrast, in the case in which the paging signalis mapped onto some subframes, a terminal which desires to receive thepaging signal does not have to receive all the subframes via which themain PMCH is transmitted and has only to receive only the part of thesubframes via which the paging signal is transmitted, and can thereforeachieve its low power consumption. Furthermore, by carrying the pagingsignal on the subframes onto which the MCCH or the main MCCH is mapped,because each mobile terminal becomes able to receive the paging signalvia the same subframes as those via which to receive the MCCH or themain MCCH, a mobile terminal which is receiving an MBMS becomes able toreceive the paging with a shorter delay time.

Each of the base stations in the MBSFN area, in step ST1782, determinesthe paging group of the mobile terminal in question. As an example ofthe determining method, there is a method of determining the paginggroup of the mobile terminal in question by using the number Kmp ofpaging groups used for the main PMCH and the received paging request.When determining the paging group of the mobile terminal in question,each of the base stations uses the same computation expression as thatused by the mobile terminal. As a concrete example, the MCE uses thesame equation as that in step ST1735, i.e., paging group=IMSI mod Kmp.When the MCE, in step ST1780, also informs the paging group of themobile terminal in question, step ST1782 can be omitted. As a result,there can be provided an advantage of reducing the control load on eachbase station in the MBSFN area, and so on. In contrast, in accordancewith the method of, in step ST1782, determining the paging group in eachbase station in the MBSFN area without informing the paging group of themobile terminal in question in step ST1780, there can be provided anadvantage of being able to reduce the amount of information notifiedfrom the MCE to each base station in the MBSFN area, and makingeffective use of the resources. Each of the base stations in the MBSFNarea, in step ST1783, transmits, instead of a PMCH, the main PMCH ontowhich the paging signal is mapped by using the identifier of the mobileterminal in question received in step ST1781, the result of thescheduling of the paging signal, the paging group of the mobile terminalin question determined in step ST1782, etc. The methods explained inEmbodiment 9 can be used as the method of mapping to the paging-relatedregion in the main PMCH at that time and the concrete method of mappingto the physical channel, etc.

The mobile terminal, in step ST1784, receives a paging-related modifiedor unmodified indicator not in a PMCH but in the main PMCH, theindicator corresponding to the paging group determined in step ST1735 ofthe mobile terminal itself. The mobile terminal, in step ST1785,determines whether or not there is a change in the paging-relatedmodified or unmodified indicator. When there is no change in thepaging-related modified or unmodified indicator, the mobile terminalmakes a transition to step ST1788. In contrast, when there is a changein the paging-related modified or unmodified indicator, the mobileterminal makes a transition to step ST1786. The mobile terminal then, instep ST1786, receives and decodes the physical area onto which thepaging-related information of the paging group of the mobile terminalitself is mapped. At that time, the mobile terminal carries out blinddetection by carrying out an operation of calculating a correlation withthe mobile-terminal-specific identification code. The mobile terminal,in step ST1787, determines whether it has detected the identifier of themobile terminal itself through the blind detection carried out in stepST1786. When the mobile terminal has not detected the identifier of themobile terminal itself, the mobile terminal makes a transition to stepST1788. In contrast, when the mobile terminal has detected theidentifier of the mobile terminal itself, the mobile terminal makes atransition to step ST1814. By configuring the method as mentioned above,each mobile terminal becomes able to receive the paging signal in thefrequency layer dedicated to MBMS irrespective of whether an MBSFN areacovering a plurality of MBSFN areas exists.

In this embodiment, the method of transmitting a paging request from anMME to an MCE, like that shown in Embodiment 2, is shown. As anothermethod, a paging request can be transmitted from an MME to an MBMS GW,instead of transmitting a paging request from an MME to an MCE. Moreconcretely, a paging request can be transmitted from an MME to an MBMSCP in an MBMS GW. This is because the channel onto which the pagingsignal is mapped is transmitted via a multi-cell transmission scheme inthe MBSFN synchronization area. The MBMS CP which has received thepaging request transmits the paging request directly to an eNB withoutmaking it pass through an MCE. In this case, what is necessary is justto newly provide an IF between the MME 103 and the MBMS GW802 or theMBMS CP 802-1 in the whole architecture of the mobile communicationsystem as disclosed in FIG. 10 which is used in the present invention.By using this IF, the above-mentioned paging request is transmitted fromthe MME to the MBMS GW or the MBMS CP. The MBMS GW or the MBMS CP whichhas received the paging request transmits the paging request signal toall eNBs in the MBSFN synchronization area by using an IF M1.

Next, a process at a time when paging for the mobile terminal inquestion occurs in this case will be explained. In step ST1773, pagingto the mobile terminal in question occurs. The MME in which paging hasoccurred, in step ST1774, checks to see the TA list of the mobileterminal in question on the basis of an identifier (UE-ID, IMSI, S-TMSI,or the like) of the mobile terminal in question for which the paging isdestined. The MME, in step ST1775, determines whether or not theTA(MBMS) is included in the TA list of the mobile terminal in question.When the TA(MBMS) is not included in the tracking area list, the MMEmakes a transition to step ST1814. In contrast, when the TA(MBMS) isincluded in the tracking area list, the MME makes a transition to stepST1776. The MME, in step ST1776, transmits a paging request not to MCEsbut to MBMS CPs. As the MBMS CPs to which the MME transmits a pagingrequest, there can be considered all MBMS CPs each of which manages afrequency layer dedicated to MBMS transmission which the base stationsmanaged by the MME can receive. As an example of parameters included inthe paging request, there can be considered an identifier (UE-ID, IMSI,S-TMSI, or the like) of the mobile terminal, the TA(MBMS) number, and soon. At this time, instead of the TA(MBMS) number, either both f(MBMS)and MBSFN area IDs or an MBSFN synchronization area ID can be provided.Each of the MBMS CPs, instead of MCEs, in step ST1777, receives thepaging request. Among the MBMS CPs each of which receives the pagingrequest in step ST1778, an MBMS CP which controls either the MBSFNsynchronization area ID or both f(MBMS) and the MBSFN area IDs which areinformed thereto as a parameter included in the paging request and whichare related to the TA(MBMS) number makes preparations for pagingtransmission. As an example of the preparations for paging transmission,an MBMS CP which controls either the MBSFN synchronization area ID orboth f(MBMS) and the MBSFN area IDs determines the paging group of themobile terminal in question by using both the number Kmp of paginggroups used for the main PMCH and the received paging request. Whendetermining the paging group of the mobile terminal in question, theMBMS CP uses the same computation expression as that used by the mobileterminal.

As a concrete example, the MBMS CP uses the same equation as that instep ST1735, i.e., paging group=IMSI mod Kmp. Because the methoddisclosed in Embodiment 9 can be applied to the structure of a channelonto which a paging signal in the frequency layer dedicated to MBMStransmission is mapped, the explanation of the method will be omittedhereafter. The MBMS CP, in step ST1779, carries out scheduling of thepaging signal destined for the mobile terminal in question. Morespecifically, the MBMS CP determines to the how-manyth one ofinformation elements mapped onto the physical area allocated to thenumber of the paging group of the mobile terminal in question determinedin step ST1778 an identifier of the mobile terminal in question isallocated. By making the MBMS CP carry out this scheduling, anidentifier of the mobile terminal in question is transmitted from thesame physical resources of base stations included not in the MBSFN areabut in the MBSFN synchronization area. As a result, there can beprovided an advantage of enabling each mobile terminal to receive apaging signal benefiting from an SFN gain by receiving the main PMCHwhich is transmitted via a multi-cell transmission scheme in the MBSFNsynchronization area. The MBMS CP, in step ST1780, transmits a pagingrequest for the mobile terminal in question to the base stations in theMBSFN synchronization area. As an example of parameters included in thepaging request, an identifier (UE-ID, IMSI, S-TMSI, or the like) of themobile terminal, the result of the scheduling of the paging signalcarried out in step ST1779 (concretely, an SFN, an MBSFN subframenumber, and an information element number), etc. can be considered. Eachof the base stations in the MBSFN synchronization area, in step ST1781,receives the paging request from the MBMS CP.

Each of the base stations in the MBSFN synchronization area, in stepST1782, determines the paging group of the mobile terminal in question.As an example of the determining method, there is a method ofdetermining the paging group of the mobile terminal in question by usingthe number Kmp of paging groups used for the main PMCH and the receivedpaging request. When determining the paging group of the mobile terminalin question, each of the base stations uses the same computationexpression as that used by the mobile terminal. As a concrete example,each of the base stations uses the same equation as that in step ST1735,i.e., paging group=IMSI mod Kmp. When the MBMS CP, in step ST1780, alsoinforms the paging group of the mobile terminal in question, step ST1782can be omitted. As a result, there can be provided an advantage ofreducing the control load on each base station in the MBSFNsynchronization area, and so on. In contrast, in accordance with themethod of, in step ST1782, determining the paging group in each basestation in the MBSFN synchronization area without informing the paginggroup of the mobile terminal in question in step ST1780, there can beprovided an advantage of being able to reduce the amount of informationnotified from the MBMS CP to each base station in the MBSFNsynchronization area, and making effective use of the resources. Each ofthe base stations in the MBSFN synchronization area, in step ST1783,transmits the main PMCH onto which the paging signal is mapped by usingthe identifier of the mobile terminal in question received in stepST1781, the result of the scheduling of the paging signal, the paginggroup of the mobile terminal in question determined in step ST1782, etc.The methods explained in Embodiment 9 can be used as the method ofmapping to the paging-related region in the main PMCH at that time andthe concrete method of mapping to the physical channel, etc.

The mobile terminal, in step ST1784, receives a paging-related modifiedor unmodified indicator not in a PMCH but in the main PMCH, theindicator corresponding to the paging group determined in step ST1735 ofthe mobile terminal itself. The mobile terminal, in step ST1785,determines whether or not there is a change in the paging-relatedmodified or unmodified indicator. When there is no change in thepaging-related modified or unmodified indicator, the mobile terminalmakes a transition to step ST1788. In contrast, when there is a changein the paging-related modified or unmodified indicator, the mobileterminal makes a transition to step ST1786. The mobile terminal then, instep ST1786, receives and decodes the physical area onto which thepaging-related information of the paging group of the mobile terminalitself is mapped. At that time, the mobile terminal carries out blinddetection by carrying out an operation of calculating a correlation withthe mobile-terminal-specific identification code. The mobile terminal,in step ST1787, determines whether it has detected the identifier of themobile terminal itself through the blind detection carried out in stepST1786. When the mobile terminal has not detected the identifier of themobile terminal itself, the mobile terminal makes a transition to stepST1788. In contrast, when the mobile terminal has detected theidentifier of the mobile terminal itself, the mobile terminal makes atransition to step ST1814.

By configuring the method as mentioned above, each mobile terminalbecomes able to receive the paging signal in the frequency layerdedicated to MBMS irrespective of whether an MBSFN area covering aplurality of MBSFN areas exists. Although the case in which the MME andthe MBMS CP exist separately is shown above, the MBMS CP can have thefunction of the MME. Because any long-distance physical IF does not haveto be disposed between the MME (or EPC) and the MBMS GW or the MBMSCP bymaking the MBMS CP have the function of the MME, the system can beconfigured in such a way as to offer a high level of security at a lowcost, and a delay time occurring in a signal transmitted between the MME(or EPC) and the MBMS GW or MBMS CP can also be reduced. Therefore, itbecomes able to reduce a control delay time, in this case, a delay timeoccurring in the paging control.

As shown in this embodiment and Embodiment 2, the method of deriving aTA(MBMS) number in an MME and adding this TA(MBMS) number to the TA listof each mobile terminal in a case in which the tracking area in thefrequency layer dedicated to MBMS transmission is an MBSFNsynchronization area or an MBSFN area is disclosed above. The presentinvention is not limited to the TA list, and a list including mobileterminals, and f(MBMS) and an MBSFN area ID which each of the mobileterminals receives can be directly formed instead of the TA list. Inthis case, the MME, in step ST1774, has only to check to see thedirectly-formed list instead of the TA list of the UE in question.Furthermore, in this case, the MME, in steps ST1776 and ST1777, has onlyto transmit and receive f(MBMS) and the MBSFN area ID, instead oftransmitting and receiving the TA(MBMS). The MME can transmit andreceive f(MBMS) and the MBSFN area ID because the TA is provided not foreach cell, but for each MBSFN area or each MBSFN synchronization area.

In this embodiment, the case in which time division multiplexing andcode division multiplexing coexist for a PMCH provided for each MBSFNarea is explained as an example, though this embodiment can also beapplied to a case in which no overlapping MBSFN areas exist, and eitherTDM or CDM exists for a PMCH provided for each MBSFN area.

As a result, there can be disclosed a method of transmitting a pagingsignal to a mobile terminal currently receiving an MBMS service in afrequency layer dedicated to MBMS transmission, and a mobilecommunication system which enables the method to be implemented therein,which are a challenge of the present invention. Therefore, there isprovided an advantage of enabling even a mobile terminal currentlyreceiving an MBMS service in the frequency layer dedicated to MBMStransmission to receive a paging signal.

By using the method of transmitting a paging signal in a frequency layerdedicated to MBMS transmission, which is disclosed in this embodiment,each mobile terminal is enabled to receive a paging signal by receivingMBSFN subframes onto which a main PMCH is mapped in a similar way evenif the mobile terminal is receiving or trying to receive an MBMS servicein any MBSFN area. Therefore, there is provided an advantage of beingable to simplify the process also when each mobile terminal changes theMBSFN area which the mobile terminal receive to receive the MBMSservice.

Embodiment 17

In Embodiment 2, the method of transmitting a paging signal from allcells in an MBSFN area each of which transmits an MBMS service which amobile terminal is receiving or trying to receive is disclosed.Furthermore, in Embodiment 16, the method of transmitting a pagingsignal from all cells in an MBSFN synchronization area is disclosed.However, it can also be expected that an MBSFN area and an MBSFNsynchronization area are huge areas geographically. In such a case,transmission of a paging signal destined for a mobile terminal from acell which does not contribute to SFN combining in the mobile terminalcauses wasted radio resources and hence reduction in the systemcapacity. Therefore, there is a necessity to limit the cells each ofwhich transmits a paging signal to a mobile terminal to a cell in whichthe mobile terminal is being located, and neighboring cells. In order tosatisfy this necessity, a method of defining a serving cell on a unicastside of a mobile terminal and an arbitrary MBMS dedicated cellgeographically corresponding to the mobile terminal as a tracking areaof the mobile terminal, and transmitting a paging signal from some cellsin an MBSFN area (or in an MBSFN synchronization area) belonging to thistracking area will be disclosed hereafter. An explanation will be madefocusing on a portion different from Embodiment 2. Portions which willnot be explained specifically are the same as those explained inEmbodiment 2.

In order to limit the cells each of which transmits a paging signal to amobile terminal to a cell in which the mobile terminal is being located,and neighboring cells, arbitrary MBMS dedicated cells geographicallycorresponding to a tracking area on a unicast side of the mobileterminal and located in an MBSFN area or an MBSFN synchronization areafrom which the mobile terminal is receiving or trying to receive an MBMSare defined as a tracking area. Abase station for a frequency layerdedicated to MBMS has an arrangement position which is shared with acell in a unicast/mixed frequency layer in such a way as to be locatedat the same position as the cell, though the base station is configuredin such a way as to have both devices (an antenna and so on) used forthe frequency layer dedicated to MBMS, and those used for theunicast/mixed frequency layer. In order to offer an MBMS service inspot, the base station for the frequency layer dedicated to MBMS can bedisposed in a part of a cell in the unicast/mixed frequency layer. Inorder to bring the tracking area on the unicast side into geographicalcorrespondence with the tracking area of the MBMS dedicated cell, a cellfor the frequency layer dedicated to MBMS which is the same as a cell inthe tracking area in the unicast/mixed frequency layer has only to bedefined as a cell in the tracking area in the former case. In the lattercase, a cell for the frequency layer dedicated to MBMS existing in thetracking area in the unicast/mixed frequency layer has only to bedefined as a cell in the tracking area. FIG. 80 shows a view in whicharbitrary MBMS dedicated cells in one MBSFN area are defined as atracking area as an example. In one MBSFN area (MBSFN area 1) in thefrequency layer dedicated to MBMS transmission, MBMS dedicated cells (atracking area TA(MBMS) #1 in the frequency layer dedicated to MBMStransmission) shown by sloped lines, and MBMS dedicated cells which arenot shown by any sloped lines are configured. In the figure, theTA(MBMS) is configured in such a way as to geographically correspond tothe tracking area (TA(unicast) #1) in the unicast/mixed frequency layer.Each MBMS dedicated cell in TA(MBMS) #1 transmits a paging signal, andany other MBMS dedicated cell does not transmit a paging signal. In thiscase, a cell which transmits a paging signal to a mobile terminal and acell which does not transmit any paging signal to the mobile terminalmay exist within an identical MBSFN area (or an identical MBSFNsynchronization area), and signals different between the cells may betransmitted to the mobile terminal via a transmission scheme which isnot a multi-cell transmission one. Because each mobile terminal cannotselectively limit the cells from each of which it receives a pagingsignal, each mobile terminal also receives a signal which is transmittedvia a transmission scheme which is not a multi-cell transmission schemeand this results in a receive error being caused therein.

A different signal transmitted from a cell which does not transmit anypaging signal causes degradation in the quality of reception of thedesired paging signal. Particularly, a mobile terminal being located inthe vicinity of a boundary between a cell which transmits a pagingsignal and a cell which does not transmit any paging signal has anincreasing number of receive errors, and therefore has a problem ofbecoming unable to receive the paging signal therefor. The configurationof a channel for paging signal to solve these problems is disclosed inEmbodiment 10. Hereafter, the method disclosed in Embodiment 10 isapplied to the channel configuration for paging signal. A case in whichcode division multiplexing is performed on a PMCH provided for eachMBSFN area will be explained as an example. The configuration of a PMCHprovided for each MBSFN area is shown in FIG. 40. A cell #n1 is onelocated in an MBSFN area 1, a cell #n2 is one located in an MBSFN area2, and a cell #n3 is one located in an MBSFN area 3. In the cell #n1,the PMCH corresponding to the MBSFN area 1 is transmitted, in the cell#n2, the PMCH corresponding to the MBSFN area 2 is transmitted, and inthe cell #n3, the PMCH corresponding to the MBSFN area 3 is similarlytransmitted. In this case, the PMCH can be continuous or discontinuousin time. In a case in which the PMCH is discontinuous in time, thelength of each of repetition periods at which an MBSFN frame cluster(MBSFN frame cluster) via which the PMCH corresponding to the MBSFN areais transmitted is repeated is expressed as the MBSFN frame clusterrepetition period length. In contrast, in a case in which the PMCH iscontinuous in time, the MBSFN frame cluster repetition period length canbe set to 0 or it is not necessary to specify this repetition period. AnMCCH and an MTCH can be divided in time and mapped onto the PMCH, andcan be further divided in time and mapped onto a physical area which istransmitted via a multi-cell transmission scheme. For example, the MCCHand the MTCH can be mapped onto different MBSFN subframes which are aphysical area onto which they are mapped as a result. The length of eachof repetition periods at which the MCCH is repeated is expressed as theMCCH repetition period length.

As to the configuration of a physical area for paging signal, the methodof carrying a paging signal, as well as an MCCH, onto a PMCH, asdisclosed in FIG. 46, the method of mapping a paging signal onto a PMCHas one information element of an MCCH, the method of using an indicator,the method of dividing mobile terminals into paging groups, the methodof providing a paging dedicated channel and carrying a paging signalonto the paging dedicated channel, as disclosed in FIG. 42, or themethod of providing a main PMCH and carrying a paging signal onto themain PMCH, as disclosed in FIG. 49, can be applied. A cell whichtransmits a paging signal and a cell which does not transmit any pagingsignal are made to use different methods when mapping a paging signalonto a physical area onto which the paging signal is mapped. Forexample, in a case in which a cell which transmits a paging signal to amobile terminal for which an incoming call is occurring, and a cellwhich does not transmit any paging signal to the mobile terminal existwithin an MBSFN area, more specifically, in a cell which transmits apaging signal to a mobile terminal for which an incoming call isoccurring, a base station connects a switch 2401 thereof to a terminal aby using this switch, as disclosed in FIG. 50. The base station thenmultiplies the paging signal to the mobile terminal by an identificationnumber specific to the mobile terminal, adds a CRC to the result of themultiplication, and carries out a process including encoding and ratematching. Because the switch 2401 is connected to the terminal a,information processed as above for each mobile terminal is allocated toa control information element unit. In a cell which does not transmitany paging signal to the mobile terminal for which an incoming call isoccurring, abase station connects a switch 2401 thereof to a terminal bby using this switch, as disclosed in FIG. 50. A code for padding foreach cell is provided without using the paging signal destined for themobile terminal, and this code for padding is allocated to a controlinformation element unit.

In this case, a control information element unit allocated to a mobileterminal has an area which is the same for both a cell which transmits apaging signal to the mobile terminal and the cell which does nottransmit any paging signal to the mobile terminal. Accordingly, eachbase station can easily switch between pieces of information to beallocated to a mobile terminal by using the switch thereof according towhether the base station exists in a cell which transmits a pagingsignal to the mobile terminal or a cell which does not transmit anypaging signal to the mobile terminal. In addition, by making the size ofthe area of a control information element unit allocated to a mobileterminal be equal for each of all mobile terminals, the length of thecode for padding defined for each cell can be predetermined. As aresult, a control operation of embedding the code for padding can besimplified. As a concrete example of the code for padding for each celldisposed in a cell which does not transmit any paging signal, the codeis set to all 0s or all 1s, as shown in FIG. 51. By providing the codefor padding in this way, each mobile terminal can cancel components of“0” or “1” transmitted from a cell which does not transmit any pagingsignal to the mobile terminal by using an interference eliminationfunction, such as an interference canceller, in the receiver thereof,and becomes able to carry out SFN combining of only the paging signaltransmitted from a cell which transmits the paging signal. The code forpadding can be alternatively set to a random value. In this case, arandom value is derived for each cell, and padding with this randomvalue is carried out. By configuring the code for padding in this way,because signals transmitted from cells each of which does not transmitany paging signal to a mobile terminal are random signals which differfrom one another, they are canceled out in the mobile terminal andtherefore the paging signal component transmitted from a cell whichtransmits the paging signal to the mobile terminal becomes strongrelatively. Therefore, it becomes able to reduce receive errorsoccurring in the paging signal in the correlation operation. Therefore,even in a case in which a cell which transmits a paging signal to amobile terminal and a cell which does not transmit any paging signal tothe mobile terminal exist in an MBSFN area, the mobile terminal becomesable to receive the paging signal. Because the detailed configuration ofthe channel for paging signal is explained in Embodiment 10, theexplanation of the detailed configuration will be omitted hereafter.

Next, a tracking area (TA) list at a frequency dedicated to MBMStransmission will be explained. In order to limit the cells each ofwhich transmits a paging signal to a mobile terminal to a cell in whichthe mobile terminal is being located, and neighboring cells, arbitraryMBMS dedicated cells geographically corresponding to a tracking area ona unicast side of the mobile terminal and located in an MBSFN area or anMBSFN synchronization area from which the mobile terminal is receivingor trying to receive an MBMS are defined as a tracking area (TA(MBMS)).In this example, a method of defining arbitrary MBMS dedicated cells inan MBSFN area from which a mobile terminal is receiving or trying toreceive an MBMS as a TA will be explained. In Embodiment 2, a TA list ofeach mobile terminal is shown in FIG. 31[a], and a table showing acorrespondence between a tracking area (TA(unicast)) in theunicast/mixed frequency layer and cells belonging is shown in FIG.31[b]. These TA list and table can be applied also to this embodiment.In Embodiment 2, a table for associating f(MBMS) and an MBSFN area IDwith a TA(MBMS) number, as shown in FIG. 31[c], is provided so as tomake it possible to derive a tracking area in the frequency layerdedicated to MBMS transmission from f(MBMS) and the ID of an MBSFN areawhich a mobile terminal is receiving or trying to receive an MBMS. Inthis embodiment, because a cell which transmits a paging signal to amobile terminal and a cell which does not transmit any paging signal tothe mobile terminal exist in an MBSFN area, a tracking area in thefrequency layer dedicated to MBMS transmission cannot be simply broughtinto correspondence with f(MBMS) and an MBSFN area ID. In order to solvethis problem, a table for associating a TA(MBMS) ID with f(MBMS) and aTA (unicast) ID is provided, and a table for associating a TA(MBMS) IDwith an MBMS transmission dedicated cell geographically corresponding toa TA(unicast) is further provided. A concrete example of the tablesshowing a TA(MBMS) is shown in FIG. 81. The table for associating aTA(MBMS) ID with f(MBMS) and a TA(unicast) ID is shown in FIG. 81[a],and the table for associating a TA(MBMS) ID with an MBMS transmissiondedicated cell geographically corresponding to a TA (unicast) is shownin FIG. 81[b]. By specifying an MBMS transmission dedicated cellgeographically corresponding to a TA (unicast) by using a TA(MBMS), andlimiting paging signal transmission to a cell in this TA(MBMS) on thebasis of these tables, it becomes able to provide a cell which transmitsa paging signal to a mobile terminal and a cell which does not transmitany paging signal to the mobile terminal as cells in an MBSFN area.

The details of management of a TA list will be explained. The methodabout the MBMS side receiving state, which is disclosed in Embodiment 2,can be applied. In this case, in a process of determining the TA(MBMS)of a mobile terminal in question, an MME, in step ST1746 of FIG. 20,determines the tracking area on the basis of a TA (unicast) ID and anotification of the MBMS side receiving state of the mobile terminal.More specifically, the MME can determine the tracking area on the basisof parameters of the MBMS side receiving state as a concrete example ofthe notification of the MBMS side receiving state, more concretely,f(MBMS) included in the parameters. In the management of the trackingarea list of the mobile terminals in question in step ST1747, the MMEsearches for a TA(MBMS) number which it manages therein on the basis off(MBMS) received in step ST1745 and the TA (unicast) determined in stepsST1714 to ST1716 so as to change the tracking area list. As a concretesearching method, the table as shown in FIG. 81[a] is used. Next, theMME determines whether the TA(MBMS) which has been searched for as theresult of the search exists in the TA list (FIG. 31[a]) of the mobileterminal in question. When the TA(MBMS) exists in the TA list, the MMEstores the current TA list. In contrast, when the TA(MBMS) does notexist in the TA list, the MME adds the above-mentioned TA(MBMS) to theTA list of the mobile terminal in question. By changing a part of theprocess of making a notification of the MBMS side receiving statedisclosed in Embodiment 2 as mentioned above, the management of a TA inaccordance with this embodiment can be implemented.

In the above-mentioned example, the mobile terminal, in ST1742, informsthe number of an MBSFN area from which it is receiving or trying toreceive an MBMS to the serving cell, and the serving cell, in ST1744,informs this MBSFN area number to the MME, like in the case ofEmbodiment 2. However, in the invention related to this embodiment, theMBSFN area number information is not required in the management of theTA(MBMS). Therefore, there is no necessity to inform the MBSFN areanumber in steps ST1742 and ST1744, and therefore the amount of signalingbetween the mobile terminal and the serving cell and between the servingcell and the MME can be reduced.

Next, the details of a process at a time when paging for the mobileterminal in question occurs in this embodiment will be explained.Hereafter, a case of transmitting a paging signal from an arbitrary MBMSdedicated cell geographically corresponding to a serving cell on aunicast side of a mobile terminal and located in an MBSFN area in orderto limit the cells each of which transmits a paging signal to the mobileterminal to a cell in which the mobile terminal is being located, andneighboring cells will be explained. In a process of carrying outdiscontinuous reception at the time of MBMS reception disclosed inEmbodiment 2, a tracking area (TA(MBMS)) in a frequency layer dedicatedto MBMS transmission is configured in such a way as to be associatedwith a tracking area (TA (unicast)) in a unicast/mixed frequency layer,as mentioned above. Furthermore, a method of mapping a paging signal isimplemented in such a way that it is changed to allocate differentpieces of information in a cell according to whether the cell is a cellwhich transmits a paging signal or a cell which does not transmit anypaging signal. An explanation will be made more concretely. Paging for amobile terminal in question occurs in step ST1773. The MME in whichpaging has occurred, in step ST1774, checks to see the TA list of themobile terminal in question on the basis of an identifier (UE-ID, IMSI,S-TMSI, or the like) of the mobile terminal in question for which thepaging is destined. The MME, in step ST1775, determines whether or notthe TA(MBMS) is included in the TA list of the mobile terminal inquestion. As a concrete example, the MME searches through the trackingarea list of the mobile terminal in question, such as a list as shown inFIG. 31[a], on the basis of the UE-ID. In a case in which the mobileterminal in question is the UE#1 (UE-ID#1) of FIG. 31[a], the MMEdetermines that the TA(MBMS) is not included in the tracking area list.In contrast, in a case in which the mobile terminal in question is theUE#2 (UE-ID#2) of FIG. 31[a], the MME determines that the TA(MBMS) isincluded is the tracking area list because the TA(MBMS) #1 is includedin the list. When the TA(MBMS) is not included in the tracking arealist, the MME makes a transition to step ST1814. In contrast, when theTA(MBMS) is included in the tracking area list, the MME makes atransition to step ST1776.

The MME, in step ST1776, transmits a paging request to MCEs. As the MCEsto which the MME transmits a paging request, there can be considered allMCEs each of which manages base stations which geographically overlapthe base stations managed by the MME. Furthermore, the MME can be madeto have one or more pieces of MCE information corresponding to eachfrequency layer dedicated to MBMS transmission (f(MBMS)), and cantransmit a paging request to one or more MCEs corresponding to f(MBMS)informed from the mobile terminal on the basis of f(MBMS). This methodcan also be used in Embodiment 2. As an example of parameters includedin the paging request, there can be considered an identifier (UE-ID,IMSI, S-TMSI, or the like) of the mobile terminal, the TA(MBMS) number,and so on. At this time, instead of the TA(MBMS) number, both f(MBMS)and a TA(unicast) number can be provided. Each of the MCEs, in stepST1777, receives the paging request. Among the MCEs each of whichreceives the paging request in step ST1778, an MCE which controls theMBMS dedicated cell which is related to either the TA(MBMS) number orboth f(MBMS) and the TA (unicast) number which are informed thereto as aparameter included in the paging request makes preparations for pagingtransmission. As a concrete example of the paging transmissionpreparations, the same method as that shown in Embodiment 2 can beapplied. The MCE which controls the MBMS dedicated cell determines thepaging group of the mobile terminal in question by using the numberKMBMS of paging groups of the self-base station (the MBSFN area to whichthe base stations belong), and the received paging request. Whendetermining the paging group of the mobile terminal in question, the MCEuses the same computation expression as that used by the mobileterminal. As a concrete example, the MCE uses the same equation as thatin step ST1735, i.e., paging group=IMSI mod KMBMS. As mentioned above,because the MCE which has received the paging request implements themethod of bringing a TA(MBMS) number into correspondence with an MBMSdedicated cell, more specifically, forms the table showing thecorrespondence information as shown in FIG. 81[b] therein in the case ofthis embodiment, instead of the table as shown in FIG. 31[c] in the caseof Embodiment 2, and the method of deriving the correspondence canprovide a relation between an MBMS dedicated cell and an MCE whichcontrols this cell only within the architecture of MBMS services, thatis, because the relation can be provided regardless of the MME, therecan be provided an advantage of becoming able to make the mobilecommunication system have a high degree of flexibility.

The MCE, in step ST1779, carries out scheduling of the paging signaldestined for the mobile terminal in question. More specifically, the MCEdetermines to the how-manyth one of information elements mapped onto thephysical area allocated to the number of the paging group of the mobileterminal in question determined in step ST1778 an identifier of themobile terminal in question is allocated. By making the MCE carry outthis scheduling, an identifier of the mobile terminal in question istransmitted from the same physical resources of base stations includedin the MBSFN area. As a result, there can be provided an advantage ofenabling the mobile terminal to receive the paging signal benefitingfrom an SFN gain by receiving an MCCH which is transmitted via amulti-cell transmission scheme in the MBSFN area. The MCE, in stepST1780, transmits a paging request for the mobile terminal in questionto base stations each of which is an MBMS dedicated cell included in theMBSFN area which the MCE controls. As an example of parameters includedin the paging request, in addition to an identifier (UE-ID, IMSI,S-TMSI, or the like) of the mobile terminal, the result of thescheduling of the paging signal carried out in step ST1779 (concretely,SFN, an MBSFN subframe number, and an information element number), etc.,which are disclosed in Embodiment 2, paging transmission enable ordisable information can be considered. The paging transmission enable ordisable information which is newly provided in this embodiment is theinformation showing whether or not each MBMS dedicated cell transmits apaging signal. As a concrete example of the paging transmission enableor disable information, 1-bit information (“1” or “0”) is provided. TheMCE, in ST1780, transmits the paging transmission enable information of“1” to each MBMS dedicated cell existing in the table of FIG. 81[b] byusing this table. In contrast, the MCE transmits the paging transmissiondisable information of “0” to each MBMS dedicated cell not existing inthe table of FIG. 81[b]. By disposing the information showing pagingtransmission enable or disable and then transmitting this informationfrom the MCE to each MBMS dedicated cell, it becomes able to provide acell which transmits a paging signal and a cell which does not transmitany paging signal.

Each of the base stations in the MBSFN area which the MCE controls, instep ST1781, receives the paging request from the MCE. Each base stationwhich is an MBMS dedicated cell existing in the TA(MBMS) shown in FIG.81[b] receives the paging signal enable information while each basestation which is an MBMS dedicated cell not existing in the TA(MBMS)receives the paging signal disable information.

Instead of disposing an IF between MME and MCE between the MME 103 andthe MCE 801, an MME-MBMS GW interface can be disposed between the MME103 and an MBMS GW 802 (in more detail, an MBMS CP 802-1). Furthermore,the processes of steps ST1776 to ST1780, which are carried out by theMCE, can be carried out by the MBMS GW on behalf of the MCE. In thisvariant, the same advantages as those provided by the present inventionare provided.

Furthermore, a case in which the MME manages the cell IDs of an MBMSdedicated cell and/or a mixed cell related to a TA(MBMS) number as shownin FIG. 81[b] is considered. In this case, the MME, in step ST1776,transmits the paging request to each MBMS dedicated cell included inMBSFN area which is managed not by an MCE but by the MME. As theparameters included in the paging request at that time, theabove-mentioned paging transmission enable or disable information can beprovided in addition to an identifier of the mobile terminal, etc. TheMME transmits the paging transmission enable information of “1” to eachMBMS dedicated cell included in the TA(MBMS) number shown in FIG. 81[b],and also transmits the paging transmission disable information of “0” toeach MBMS dedicated cell not included in the TA(MBMS) number. Asmentioned above, the method (FIG. 81) of managing, in addition to aTA(unicast), the relation between a TA(MBMS) number and cells includedin the TA(MBMS) number in the MME eliminates recognition between a cellwhich transmits a paging signal to a mobile terminal and a cell whichdoes not transmit any paging signal to the mobile terminal in an MCE,and the process of transmitting dedicated paging transmission enable ordisable information to each cell according to the results of therecognition. Because this results in elimination of the necessity to addany function to each MCE, there can be provided an advantage of beingable to avoid the complexity of each MCE. Furthermore, there can beprovided an advantage of being able to reduction the processing load oneach MCE.

Each of the base stations in the MBSFN area, in step ST1782, determinesthe paging group of the mobile terminal in question. As a concreteexample of a method of determining the paging group, the same method asthat shown in Embodiment 2 can be applied. Each of the base stationsdetermines the paging group of the mobile terminal in question by usingthe number KMBMS of paging groups of the self-base station (the MBSFNarea to which the base stations belong), and the received pagingrequest. When determining the paging group of the mobile terminal inquestion, each of the base stations uses the same computation expressionas that used by the mobile terminal. As a concrete example, the MCE usesthe same equation as that in step ST1735, i.e., paging group=IMSI modKMBMS. When the MCE, in step ST1780, also informs the paging group ofthe mobile terminal in question, step ST1782 can be omitted. As aresult, there can be provided an advantage of reducing the control loadon each base station in the MBSFN area. In contrast, in accordance withthe method of, in step ST1782, determining the paging group in each basestation in the MBSFN area without informing the paging group of themobile terminal in question in step ST1780, there can be provided anadvantage of being able to reduce the amount of information notifiedfrom the MCE to each base station in the MBSFN area, and makingeffective use of the resources. Each of the base stations in the MBSFNarea, in step ST1783, transmits a PMCH by carrying the paging signal,the code for padding, or the like onto the PMCH by using the identifierof the mobile terminal in question received in step ST1781, the resultof the scheduling of the paging signal, the paging group of the mobileterminal in question determined in step ST1782, etc. A cell which hasreceived the transmission enable information of “1” as the pagingtransmission enable or disable information, in ST1781, carries thepaging signal onto a PMCH, and maps the PMCH onto MBSFN subframescorresponding to the MBSFN area to transmit the PMCH. In contrast, acell which has received the transmission disable information of “0” asthe paging transmission enable or disable information, in ST1781, padsnot a paging signal but a code for padding with an identical informationelement number and maps the code for padding onto MBSFN subframescorresponding to the MBSFN area to transmit the code for padding.Because the method of mapping a paging signal onto a paging related areain a PMCH, and the method of changing the mapping method of mapping apaging signal onto a physical area onto which the paging signal ismapped between a cell which transmits a paging signal and a cell whichdoes not transmit any paging signal are explained in detail inEmbodiment 2 and Embodiment 10, the explanation of the methods will beomitted hereafter.

The mobile terminal, in step ST1784, receives a paging-relatedinformation presence or absence indicator transmitted from all the cellsin the MBSFN area in ST1783. Like in the case of Embodiment 2, each MBMSdedicated cell, in step ST1783, maps the paging-related informationpresence or absence indicator onto the physical area corresponding tothe paging group of the mobile terminal in question determined inST1782. Therefore, the mobile terminal has only to receive the physicalarea corresponding to the paging group of the mobile terminal itselfwhich the mobile terminal, in step ST1735, determines by using the sameequation. The length of the repetition period of the paging-relatedinformation presence or absence indicator and the physical area can betransmitted via broadcast information from a serving cell for unicastservice, can be transmitted via broadcast information from an MBMSdedicated cell, or can be predetermined. The mobile terminal, in stepST1785, determines whether or not there is a change in the pagingrelated modified or unmodified indicator. When there is no change in thepaging related modified or unmodified indicator, the mobile terminalmakes a transition to step ST1788. In contrast, when there is a changein the paging related modified or unmodified indicator, the mobileterminal makes a transition to step ST1786. The mobile terminal then, instep ST1786, receives and decodes the physical area onto which thepaging-related information of the paging group of the mobile terminalitself is mapped. At that time, the mobile terminal carries out blinddetection by carrying out an operation of calculating a correlation withthe mobile-terminal-specific identification code. Because MBSFNsubframes are transmitted via a multi-cell transmission scheme in anMBSFN, a transmission signal from a cell which does not transmit anypaging signal acts as noise at each mobile terminal when receiving thetransmission signal. By using the method as disclosed above, each mobileterminal can cancel the component of a code for padding transmitted froma cell which does not transmit any paging signal by using aninterference elimination function, such as an interference canceller, inthe receiver thereof, and becomes able to carry out SFN combining ofonly a paging signal transmitted from a cell which transmits the pagingsignal. In a case in which the code for padding has a random value, eachmobile terminal does not have to have the interference eliminationfunction, such as the interference canceller, in the receiver thereof.In this case, because each cell derives a random value for each cell andcarries out padding with this random value, the signals transmitted fromcells each of which does not transmit any paging signal are randomsignals which differ from one another and they are canceled out in eachmobile terminal. Therefore, the paging signal component transmitted froma cell which transmits the paging signal becomes strong relatively, andit becomes able to reduce receive errors occurring in the paging signalin the correlation operation. The mobile terminal, in step ST1787,determines whether it has detected the identifier of the mobile terminalitself through the blind detection carried out in step ST1786. When themobile terminal has not detected the identifier of the mobile terminalitself, the mobile terminal makes a transition to step ST1788. Incontrast, when the mobile terminal has detected the identifier of themobile terminal itself, the mobile terminal makes a transition to stepST1814.

By using the above-mentioned methods, there can be disclosed a method oftransmitting a paging signal to a mobile terminal currently receiving anMBMS service in a frequency layer dedicated to MBMS transmission, and amobile communication system which enables the method to be implementedtherein, which are a challenge of the present invention. Therefore,there is provided an advantage of enabling even a mobile terminalcurrently receiving an MBMS service in the frequency layer dedicated toMBMS transmission to receive a paging signal. Furthermore, even if acell which transmits a paging signal and a cell which does not transmitany paging signal coexist, it becomes able to lessen the reduction inreceive errors occurring at a time of reception of a paging signal ineach mobile terminal. Therefore, by providing a cell which transmits apaging signal and a cell which does not transmit any paging signal inthe system, it becomes able to limit the cells each of which transmits apaging signal to a mobile terminal to a cell in which the mobileterminal is being located, and neighboring cells, and therefore waste ofradio resources can be reduced and the system capacity can be increased.

In the above-mentioned concrete example, the case in which code divisionmultiplexing is performed on the PMCH provided for each MBSFN area isexplained. This embodiment can be applied not only to the case in whichcode division multiplexing is performed on the PMCH provided for eachMBSFN area but also to a case in which time division multiplexing isperformed on the PMCH provided for each MBSFN area.

The method disclosed in this embodiment can be applied not only to thecase in which the tracking area (TA(MBMS)) is constructed of arbitraryMBMS dedicated cells in one MBSFN area, but also to a case in which thetracking area (TA(MBMS)) is constructed of arbitrary MBMS dedicatedcells in a plurality of MBSFN areas as shown in FIG. 82[a]. In thiscase, among the MCEs each of which receives the paging request in stepST1778, there exist a plurality of MCEs each of which controls an MBMSdedicated cell which is related to either a TA(MBMS) number or bothf(MBMS) and a TA (unicast) number which are informed thereto as aparameter included in the paging request. In this case, each mobileterminal does not receive paging signals from all the MBMS dedicatedcells in the TA(MBMS), but receives a paging signal from an MBMSdedicated cell in the TA(MBMS) belonging to one or more MBSFN areas fromwhich the mobile terminal itself is receiving or trying to receive anMBMS. The number K of paging groups used in each MBSFN area, in stepST1728, is transmitted from an MBMS dedicated cell belonging to eachMBSFN area from which the mobile terminal itself is receiving or tryingto receive an MBMS while being mapped onto an MCCH. Each mobileterminal, in step ST1729, receives this number K of paging groups.

Also in a case in which one cell belongs to a plurality of MBSFN areasand the tracking area (TA(MBMS)) is constructed of arbitrary MBMSdedicated cells in a plurality of MBSFN areas, as shown in FIG. 82[b],the above-mentioned method can be applied. In this case, the methoddisclosed in the variant of Embodiment 7 can be applied as theconfiguration of a channel onto which a paging signal or a code forpadding is mapped, and the method disclosed in Embodiment 10 can beapplied as the method of mapping a paging signal or a code for paddingonto a physical area on a PMCH onto which the paging signal is mapped.

In the above-mentioned concrete example, the method of forming aTA(MBMS) from arbitrary MBMS dedicated cells in an MBSFN area in orderto define a tracking area in a frequency layer dedicated to MBMStransmission geographically corresponding to a serving cell on a unicastside of a mobile terminal as the TA(MBMS) is disclosed. Therefore, inthe paging operation shown in this embodiment, the mobile terminal, insteps ST1742 to ST1745, ST1776, and ST1777, does not have to carry outtransmission and reception of ID information about an MBSFN area fromwhich the mobile terminal is receiving or trying to receive an MBMS.However, in addition to the information shown in the above-mentionedconcrete example, this MBSFN area ID can be further included in theinformation transmitted and received in steps ST1742 to ST1745, ST1776,and ST1777. When this MBSFN area ID is included in the informationtransmitted and received in these steps, the MBMS dedicated cells eachof which transmits a paging signal can be further limited to the MBSFNarea having this MBSFN area ID in the case in which the tracking area(TA(MBMS)) is formed of arbitrary MBMS dedicated cells in a plurality ofMBSFN areas and in the case in which one cell belongs to a plurality ofMBSFN areas, and the tracking area (TA(MBMS)) is formed of arbitraryMBMS dedicated cells in a plurality of MBSFN areas.

The MCE which has received the paging request also including the MBSFNarea ID information in ST1777 can determine whether to transmit thepaging request to an MBMS dedicated cell from this MBSFN area ID, andcan therefore simplify its control operation. The MCE which controls theMBMS dedicated cell in this MBSFN area ID determines to transmit thepaging request to the MBMS dedicated cell, and only this MCE, in ST1780,transmits the paging request to the MBMS dedicated cell. The MBMSdedicated cell which has received the MBMS dedicated cell for the pagingrequest, i.e., the MBMS dedicated cell included in the TA(MBMS) numbershown in FIG. 81[b] transmits the paging signal on the basis of thepaging transmission enable or disable information, and an MBMS dedicatedcell which is not included in the TA(MBMS) number transmits a code forpadding instead of the paging signal. By configuring the method in thisway, because a cell in an MBSFN area from which each mobile terminal isneither receiving nor trying to receive an MBMS service does not have totransmit a paging signal, there is provided an advantage of being ableto reduce use of wasted radio resources and to increase the systemcapacity.

In the above-mentioned concrete example, the method of providing thepaging transmission enable or disable information showing whether eachMBMS dedicated cell transmits a paging signal, and enabling an MCE totransmit a paging request to an MBMS dedicated cell in the MBSFN areawhile including this paging transmission enable or disable informationin the paging request is shown. However, as shown in Embodiment 7 toEmbodiment 10, in the case in which the physical area onto which thepaging signal is mapped is determined, it is not necessary to providethe paging transmission enable or disable information, and the MCE hasonly to transmit the paging request to an MBMS dedicated cell whichtransmits the paging signal in the MBSFN area while not transmitting thepaging request to an MBMS dedicated cell which does not transmit thepaging signal. The MBMS dedicated cell which receives the paging requestfrom the MCE can map the paging signal onto a physical area for mappingthe paging signal to transmit the paging signal, whereas the MBMSdedicated cell which does not receive the paging request from the MCEcan set the output power of a physical area for mapping the pagingsignal to 0 to transmit the paging signal. By configuring the method inthis way, not only the same advantages as those provided by theabove-mentioned concrete example, but also an advantage of eliminatingthe necessity to transmit the paging request from the MCE to all thecells in the MBSFN area and reducing the amount of signaling in thesystem are provided.

In this embodiment, the method of defining arbitrary MBMS dedicatedcells geographically corresponding to a serving cell on a unicast sideof a mobile terminal as a tracking area, and transmitting a pagingsignal from some cells in an MBSFN area (or in an MBSFN synchronizationarea) belonging to this tracking area is disclosed. As a concreteexample, the case in which one tracking area is formed in an MBSFN area(or in an MBSFN synchronization area) is shown. Hereafter, a method oftransmitting a paging signal from each cell in an MBSFN area (or in anMBSFN synchronization area) in a case in which a plurality of trackingareas (TA(MBMS)s) is formed in one MBSFN area (or in one MBSFNsynchronization area) will be disclosed. In FIG. 98, A denotes afrequency layer dedicated to MBMS transmission, and B denotes aunicast/mixed frequency layer. A case in which two TA(MBMS) s (aTA(MBMS) #1 and a TA(MBMS) #2) are formed in one MBSFN area, as shown inFIG. 98, will be shown. In the case in which two TA(MBMS) s (a TA(MBMS)#1 and a TA(MBMS) #2) are formed in one MBSFN area in this way, an MBMSdedicated cell in the MBSFN area needs to transmit a paging signaldifferent for each of the tracking areas to each mobile terminal beingserved thereby. In the case in which a plurality of tracking areas(TA(MBMS)s) are formed in one MBSFN area (or in an MBSFN synchronizationarea), as mentioned above, because an MBMS dedicated cell in the MBSFNarea transmits a paging signal different for each of the tracking areas,time division multiplexing (TDM) of MBSFN subframes onto which pagingsignals for the TA(MBMS)s are mapped respectively is carried out totransmit the paging signals. In order to map the paging signals onto theMBSFN subframes, for example, the configuration of carrying a pagingsignal onto a PMCH, a DPCH, a main PMCH, or the like, which is disclosedin Embodiment 7 to Embodiment 9, can be applied. FIG. 99 shows a viewshowing TDM of the paging signals for the TA(MBMS)s and mapping of them.In the FIG. 99, A denotes an “MBSFN subframe onto which the pagingsignal for the TA(MBMS) #1 is mapped”, B denotes an “MBSFN subframe ontowhich the padding code for the TA(MBMS) #2 is mapped”, C denotes an“MBSFN subframe onto which the paging signal for the TA(MBMS) #2 ismapped”, and D denotes an “MBSFN subframe onto which the padding codefor TA(MBMS) #1 is mapped”. A cell #n1-1 is one included in the MBSFNarea #1 and belonging to the TA(MBMS) #1, and a cell #n1-2 is oneincluded in the MBSFN area #1 and belonging to the TA(MBMS) #2. As shownin the figure, time division multiplexing of the MBSFN subframe ontowhich the paging signal transmitted by the cell #n1-1 is mapped, and theMBSFN subframe onto which the paging signal transmitted by the cell#n1-2 is mapped is carried out. In the example shown in the figure, thesubframes are adjacent to each other, though they do not have to beadjacent to each other and have only to be separated from each other intime. In the MBSFN subframe onto which the paging signal transmitted bythe cell #n1-1 is mapped, the code for padding from the cell #n1-2 isalso mapped and transmitted. Furthermore, in the MBSFN subframe ontowhich the paging signal transmitted by the cell #n1-2 is mapped, thecode for padding from the cell #n1-1 is also mapped and transmitted. Asthe method of transmitting these codes for padding, the method describedin Embodiment 10 or this embodiment can be applied. Furthermore,although the code for padding is mapped and is transmitted in theexample shown in the figure, in the case in which the physical area ontowhich the paging signal is mapped is determined within each MBSFNsubframe, in the MBSFN subframe onto which the paging signal transmittedby the cell #n1-1 is mapped, the transmission power of the physical areain this MBSFN subframe onto which the paging signal from the cell #n1-2is mapped can be set to 0. Similarly, in the MBSFN subframe onto whichthe paging signal transmitted by the cell #n1-2 is mapped, thetransmission power of the physical area in this MBSFN subframe ontowhich the paging signal from the cell #n1-1 is mapped can be set to 0.As these methods, the method described in Embodiment 10 can also beapplied.

By configuring the methods in this way, a plurality of tracking areas(TA(MBMS) s) can be formed in one MBSFN area. Therefore, because thesystem can carry out the management of tracking areas with flexibility,there is no necessity to match the tracking area of a frequency layerdedicated to MBMS with that of a unicast/mixed frequency layer, and tomake the tracking area of an MBSFN area be the same as that of theunicast/mixed frequency layer. Therefore, there is provided an advantageof being able to carry out cell arrangement in each layer withflexibility. In the future, even in a case in which a large number ofcells in a frequency layer dedicated to MBMS are arranged, a mobilecommunication system will be able to be constructed by using the methodsdisclosed in this embodiment.

Embodiment 18

In this embodiment, with reference to FIG. 83, “broadcasting regarding areceivable MBMS”, “search for an MBMS”, and “MBMS service selection”,among the processes carried out by the mobile communication systemdescribed in Embodiment 1 and 2, will be further explained. A servingcell, in step ST3501 of FIG. 83, transmits information about areceivable MBMS to each mobile terminal. Furthermore, the serving cellcan transmit information about a receivable MBMS within the self-cell toeach mobile terminal. The serving cell is a base station which carriesout scheduling (Scheduling) so as to carry out allocation of uplinkradio resources and downlink radio resources to a mobile terminal inquestion. As a base station which can become the serving cell, there isa unicast cell or an MBMS/unicast-mixed cell. As a concrete example ofthe information about a receivable MBMS, one or more frequencies of oneor more available MBMS services, i.e., one or more frequencies of areceivable MBSFN synchronization area (MBSFN Synchronization Area),i.e., one or more frequencies (referred to as one or more f(MBMS)) of areceivable frequency layer dedicated to MBMS transmission are informed.When transmitting the information about a receivable MBMS from theserving cell to each mobile terminal, a broadcast control channel (BCCH)is used. The information about a receivable MBMS is first mapped ontothe broadcast control channel (BCCH) which is a logical channel, andthis broadcast control channel is further mapped onto a broadcastchannel (BCH) which is a transport channel and this broadcast channel ismapped onto a physical broadcast channel (PBCH) which is a physicalchannel. As an alternative, after the information about a receivableMBMS is mapped onto the broadcast control channel (BCCH) which is alogical channel, the broadcast control channel can be mapped onto adownlink shared channel (DL-SCH) which is a transport channel, and thedownlink shared channel can be mapped onto a physical downlink sharedchannel (PDSCH) which is a physical channel.

Each mobile terminal, in step ST3502, receives f(MBMS) transmitted fromthe serving cell. In this case, there is an issue of how the servingcell, in step ST3501, acquires the information about a receivable MBMS,which is informed from the serving cell to the mobile terminal. Morespecifically, if the information about a receivable MBMS is not changedfrequently but is determined semi-statically (semi-static), theinformation about a receivable MBMS can be set to the serving cell everytime when it is changed. As an alternative, the information about areceivable MBMS can be transmitted from a control device in a frequencylayer dedicated to MBMS transmission to a control device in aunicast/mixed frequency layer when the information is changed or atregular intervals. As a further concrete example, the information abouta receivable MBMS is transmitted from an MCE to an MME or a basestation. As an alternative, the information about a receivable MBMS canbe transmitted from an MBMS GW to an MME or a base station.

Each mobile terminal, in step ST3503, checks to see whether it hasreceived one or more frequencies of the receivable frequency layerdedicated to MBMS transmission in step ST3502. Each mobile terminal endsthe process when not having received one or more frequencies. Whenhaving received one or more frequencies, each mobile terminal makes atransition to step ST3504. Each mobile terminal, in step ST3504, checksto see whether the user has an intention of receiving an MBMS service inthe frequency layer dedicated to MBMS transmission. As an example of thechecking, when the user has an intention of receiving an MBMS service,he or she uses a user interface to send a command to his or her mobileterminal, and the mobile terminal stores information showing the user'sintention in a protocol processing unit 1101 thereof. Each mobileterminal, in step ST3504, checks to see whether or not the informationshowing the user's intention of receiving an MBMS service is stored inthe protocol processing unit 1101. When the information showing theuser's intention of receiving an MBMS service is not stored, each mobileterminal repeats the process of step ST3504. As a method of repeatingthe process, each mobile terminal uses a method of carrying out thedetermination of step ST3504 at fixed periods (cycles), or a method ofcarrying out step ST3504 or ST3503 when receiving a notification showinga change in the user's intention of receiving an MBMS service inputtedfrom the user by way of a user interface. In contrast, when theinformation showing the user's intention of receiving an MBMS service isstored, each mobile terminal makes a transition to step ST3505. Theorder of the processes of step ST3503 and step ST3504 can be arbitrary,and they can be simultaneously carried out. Each mobile terminal, instep ST3505, moves to the frequency layer dedicated to MBMS transmissionby changing the frequency set to a frequency converting unit 1107thereof to change the center frequency to f(MBMS). Changing thefrequency set to the frequency converting unit 1107 to change its centerfrequency is referred to as re-tune (re-tune).

Each mobile terminal, in step ST3506, carries out a searching operationof searching for an MBMS. Because the details of the searching operationof searching for an MBMS is described in Embodiment 2, the explanationof the searching operation will be omitted hereafter. Each mobileterminal carries out synchronization establishment with an MBMSdedicated cell, acquisition of system information about the MBMSdedicated cell, acquisition of MCCH scheduling, etc. by carrying out thesearching operation of searching for an MBMS. The MBMS dedicated cell,in step ST3507, informs the contents of MBMS services to each mobileterminal. It is described in nonpatent reference 1 that an MCE 801allocates radio resources to all base stations in an MBSFN area in orderto carry out multi-cell MBMS transmission (multi-cell MBMStransmission). It can be expected from this description that MBMSservices identical with one anther which can be subjected to SFNcombining (Combining) are provided in the MBSFN area. Therefore, thecontents of MBMS services are informed in step ST3507 for each MBSFNarea by using a channel of each MBSFN area. It is further described innonpatent reference 1 that an MBSFN synchronization area includes one ormore MBSFN areas (MBSFN Areas). According to this description, thecontents of MBMS services are informed in step ST3507 for each of allMBSFN areas included in each MBSFN synchronization area by using achannel of the MBSFN synchronization area.

As a concrete example of the contents of MBMS services, there are directservice contents, e.g., “weather forecast”, “baseball live broadcast”,and “news”. Furthermore, instead of direct service contents, servicenumbers or MBSFN area numbers (IDs) can be provided. In a case in whichthe contents of MBMS services are informed with service numbers or MBSFNarea numbers (IDs), a correspondence (refer to FIG. 84) between servicenumbers or MBSFN area numbers (IDs) and direct service contents needs tobe statically or semi-statically grasped by the network side and themobile terminal side. In a case in which the correspondence betweenservice numbers and direct service contents is determinedsemi-statically, the correspondence between service numbers and directservice contents needs to be informed from the network side to themobile terminal side every time when the correspondence is changed or atperiods (or cycles).

The correspondence between service numbers and direct service contentsis mapped onto a broadcast control channel (BCCH) which is a logicalchannel of the MBMS dedicated cell, and the broadcast control channel isfurther mapped onto a broadcast channel (BCH) which is a transportchannel and this broadcast channel is mapped onto a physical broadcastchannel (PBCH) which is a physical channel. The correspondence betweenservice numbers and direct service contents can be alternatively mappedonto the broadcast control channel (BCCH) which is a logical channel,and this broadcast control channel can be further mapped onto a downlinkshared channel (DL-SCH) which is a transport channel and the downlinkshared channel can be mapped onto a physical downlink shared channel(PDSCH) which is a physical channel. As an alternative, thecorrespondence between service numbers and direct service contents canbe mapped onto a multicast control channel (MCCH) which is a logicalchannel, and the multicast control channel can be mapped onto amulticast channel (MCH) which is a transport channel and the multicastchannel can be mapped onto a physical multicast channel (PMCH) which isa physical channel. As an alternative, the correspondence betweenservice numbers and direct service contents can be mapped onto themulticast control channel (MCCH) which is a logical channel, and themulticast control channel can be mapped onto the downlink shared channel(DL-SCH) which is a transport channel and the downlink shared channelcan be mapped onto the physical downlink shared channel (PDSCH) which isa physical channel.

Instead of the direct service contents, channel numbers or MBSFN areanumbers (IDs) can be informed from the network side to the mobileterminal side. In this case, channel numbers or MBSFN area numbers (IDs)are assumed to be channel numbers of television or the like. In thiscase, the user needs to get to know a program list of each channel(direct service contents listed in time order) separately. This programlist can be informed from the network side to the mobile terminal sideevery time when the correspondence is changed or at periods (or cycles),or can be published in an existing medium, such as a newspaper. Becausea concrete example of channels which are used for informing the programlist of each channel from the network side to the mobile terminal sideis the same as that in the case of informing the correspondence betweenservice numbers and direct service contents, the explanation of theconcrete example will be omitted hereafter. Each mobile terminal, instep ST3508, receives the contents of MBMS services which aretransmitted from the MBMS dedicated cell.

Each mobile terminal, in step ST3509, checks the contents of MBMSservices received in step ST3508 in order to know whether or not aservice which the user desires is ongoing. When the service which theuser desires is ongoing, each mobile terminal makes a transition to stepST3510. In contrast, when the service which the user desires is notongoing, each mobile terminal makes a transition to step ST3512. Eachmobile terminal, in step ST3510, receives a reference signal (RS) with aradio resource of the MBSFN area in which the service which the userdesires is ongoing, and measures the received power (RSRP) of thereference signal. Each mobile terminal further, in step ST3510,determines whether or not the received power is equal to or higher thana threshold which is determined statically or semi-statically. The factthat the received power is equal to or higher than the above-mentionedthreshold shows that each mobile terminal has high quality enough toreceive the MBMS service, whereas the fact that the received power islower than the threshold shows that each mobile terminal does not havehigh quality enough to receive the MBMS service. When the received poweris equal to or higher than the above-mentioned threshold, each mobileterminal makes a transition to step ST3511, whereas when the receivedpower is lower than the above-mentioned threshold, each mobile terminalmakes a transition to step ST3512. If each mobile terminal, in stepST3510, can determine whether or not its quality of reception is goodenough to receive the MBMS service, each mobile terminal does not haveto use the above-mentioned method of measuring the received power of thereference signal (RS). Each mobile terminal, in step ST3511, selects theMBMS service. Concretely, each mobile terminal acquires a frequencyf(MBMS) dedicated to MBMS transmission, an MBSFN area ID (number), etc.to receive the MBMS service which the user desires, and then determinesthem. Each mobile terminal, in step ST3512, determines whether or notthere is another frequency (a frequency in the frequency layer dedicatedto MBMS transmission different from the current frequency) in the one ormore frequencies (a frequency list) of a receivable MBSFNsynchronization area received in step ST3502. When another frequencyexists in the frequency list, each mobile terminal returns to stepST3505 and switches its set frequency to a new frequency (f2(MBMS)), andthen repeats the process. In contrast, when any other frequency does notexist in the frequency list, each mobile terminal ends the process.

In accordance with Embodiment 18, the method of enabling a mobileterminal to move to an MBMS transmission dedicated frequency layer andthe method of selecting a desired service, which are a challenge of thepresent invention, can be provided. In addition, because each mobileterminal can know the existence of an available MBMS service and itsfrequency at a location where the mobile terminal is being locatedgeographically, each mobile terminal does not have to search for afrequency at which a frequency layer dedicated to MBMS transmission canexist in a round-robin manner when the user of the mobile terminal hasan intention of receiving an MBMS service in the frequency layerdedicated to MBMS transmission. As a result, there is provided anadvantage of shortening a control delay time occurring before eachmobile terminal receives a service at a frequency other than acurrently-selected frequency. Accordingly, there can also be provided anadvantage of achieving low power consumption in each mobile terminal.Furthermore, compared with Embodiment 19 which will be mentioned below,the amount of information transmitted from the serving cell and requiredto solve the problem can be reduced. This means that the time requiredto receive the information from the serving cell, i.e., the receivingtime, the decode time required to decode received data, and so on becomeshort compared with Embodiment 19. As a result, there is provided anadvantage of shortening a control delay time occurring before eachmobile terminal receives a service at a frequency other than acurrently-selected frequency. Furthermore, there can be provided anadvantage of achieving low power consumption in each mobile terminal.

Variant 1

Hereafter, variant 1 of this embodiment will be explained. In a case inwhich information about peripheral cells (i.e., peripheral cellinformation (list) or neighboring cell (neighboring cell) information(list)) is transmitted from the serving cell to each mobile terminal,the information about a receivable MBMS in a neighboring cell can betransmitted from the serving cell. The information about a receivableMBMS in a neighboring cell can be transmitted at the same time when theneighboring cell information is transmitted or the information about areceivable MBMS in a neighboring cell can be transmitted but not at thesame time when the neighboring cell information is transmitted. Becausea concrete example of the information about a receivable MBMS is thesame as that shown in Embodiment 18, the explanation of the concreteexample will be omitted hereafter. Variant 1 can provide the followingadvantages. A case in which the receive sensitivity of a neighboringcell has become good in a unicast/mixed frequency layer, i.e., a time tocarry out a handover has come will be considered. When f(MBMS) at whicha mobile terminal is currently receiving an MBMS does not exist in theinformation regarding a receivable MBMS in a base station which isselected newly as a serving cell (a new serving cell: New Serving cell,i.e., a handover destination base station), the mobile terminal candetermine that the sensitivity of the reception of the service which itis currently receiving at f(MBMS) will get worse if it continues tomove. The result of this determination can be notified to the userthrough display of it on a display unit, with an alarm, or the like. Asa result, when the user gives a higher priority to the current receptionof the MBMS service than to the movement, the user becomes able to stopthe movement, and there can be provided an advantage of enabling theuser to use the mobile terminal according to the user's needs moreeffectively. Furthermore, when the sensitivity of the reception of theservice which the mobile terminal is currently receiving at f1(MBMS)gets worse, if f2 (MBMS) does not exist in the information about areceivable MBMS in the serving cell (self-cell), but exists in theinformation about a receivable MBMS in a neighboring cell, the mobileterminal can try to carry out an operation of searching for an MBMS atf2 (MBMS), or the like. As a result, there can be provided an advantageof enabling the user to use the mobile terminal according to the user'sneeds more effectively.

Embodiment 19

In this embodiment, with reference to FIG. 85, “broadcasting regarding areceivable MBMS”, “search for an MBMS”, and “MBMS service selection”,among the processes carried out by the mobile communication systemdescribed in Embodiment 1 and 2, will be further explained. In FIG. 85,because the same steps as those shown in FIG. 83 denote the sameprocesses as those shown in the figure or like processes, theexplanation of the steps will be omitted hereafter. A serving cell, instep ST3701, transmits information about a receivable MBMS to eachmobile terminal. Furthermore, the serving cell transmits informationabout a receivable MBMS within the self-cell to each mobile terminal. Asa concrete example of the information about a receivable MBMS, one ormore frequencies of one or more available MBMS services, i.e., one ormore frequencies of a receivable MBSFN synchronization area (MBSFNSynchronization Area), i.e., one or more frequencies (referred to as oneor more f(MBMS)) of a receivable frequency layer dedicated to MBMStransmission are informed. Furthermore, service contents receivable atabove-mentioned f(MBMS) can be informed. The above-mentioned f(MBMS) andthe service contents receivable at f(MBMS) can be transmittedsimultaneously or unsimultaneously. Because a concrete example of achannel used for transmitting the information about a receivable MBMS isthe same as that shown in Embodiment 18, the explanation of the concreteexample will be omitted hereafter. Furthermore, because a concreteexample of the service contents is the same as that shown in Embodiment18, the explanation of the concrete example will be omitted hereafter.Each mobile terminal, in step ST3702, receives f(MBMS) and the servicecontents receivable at f(MBMS) which are transmitted from the servingcell. In this case, there is an issue of how the serving cell, in stepST3701, acquires the information about a receivable MBMS, which istransmitted from the serving cell to each mobile terminal. Morespecifically, if the information about a receivable MBMS is not changedfrequently but is determined semi-statically (semi-static), theinformation about a receivable MBMS can be set to the serving cell everytime when it is changed. Furthermore, the information about a receivableMBMS can be transmitted from a control device in a frequency layerdedicated to MBMS transmission to a control device in a unicast/mixedfrequency layer when the information is changed or at regular intervals.As a further concrete example, the information about a receivable MBMSis transmitted from an MCE to an MME or a base station. As analternative, the information about a receivable MBMS can be transmittedfrom an MBMS GW to an MME or abase station. Each mobile terminal, instep ST3504, checks to see whether the user has an intention ofreceiving an MBMS service in the frequency layer dedicated to MBMStransmission. When the user has an intention of receiving an MBMSservice in the frequency layer dedicated to MBMS transmission, eachmobile terminal makes a transition to step ST3703. In contrast, when theuser does not have an intention of receiving an MBMS service in thefrequency layer dedicated to MBMS transmission, each mobile terminalrepeats the process of step ST3504.

Each mobile terminal, in step ST3703, checks to see whether it hasreceived one or more frequencies of a receivable frequency layerdedicated to MBMS transmission, which is carrying out the service whichthe user desires, in step ST3702. Each mobile terminal ends the processwhen not having received one or more frequencies. In contrast, whenhaving received one or more frequencies, each mobile terminal makes atransition to step ST3704. For example, it is assumed that one frequencyof a receivable frequency layer dedicated to MBMS transmission, which iscarrying out the service which the user desires, is fa(MBMS). Eachmobile terminal, in step ST3704, moves to the receivable frequency layerdedicated to MBMS transmission which is carrying out the service whichthe user desires by changing the frequency set to a frequency convertingunit 1107 thereof to change the center frequency to fa(MBMS). Eachmobile terminal, in step ST3506, carries out a searching operation ofsearching for an MBMS. The MBMS dedicated cell, in step ST3507, informsthe contents of MBMS services to each mobile terminal. Each mobileterminal, in step ST3508, receives the contents of MBMS services fromthe MBMS dedicated cell. Each mobile terminal, in step ST3510,determines whether the sensitivity of reception of the MBSFN area inwhich the service which the user desires is ongoing is good enough toreceive. When the quality of reception is good enough to receive, eachmobile terminal makes a transition to step ST3511. In contrast, when thequality of reception is not good enough to receive, each mobile terminalmakes a transition to step ST3705. Each mobile terminal, in step ST3511,selects the MBMS service. Each mobile terminal, in step ST3705,determines whether or not there is another frequency (a frequency in thefrequency layer dedicated to MBMS transmission different from thecurrent frequency) at which the service which the user desires isongoing in the one or more frequencies (a frequency list) of areceivable MBSFN synchronization area received in step ST3702. Whenanother frequency exists in the frequency list, each mobile terminalreturns to step ST3704 and changes the frequency set to the synthesizerthereof to a new frequency, e.g., f2(MBMS), and then repeats theprocess. In contrast, when any other frequency does not exist in thefrequency list, each mobile terminal ends the process.

In accordance with Embodiment 19, the method of enabling a mobileterminal to move to an MBMS transmission dedicated frequency layer andthe method of selecting a desired service, which are a challenge of thepresent invention, can be provided. Compared with Embodiment 18, thefollowing advantages in solving the problem can be provided. InEmbodiment 18, there is provided no means of enabling each mobileterminal to get to know whether the service which the user desires isongoing in a frequency layer dedicated to MBMS transmission beforechanging the frequency and then moving to the frequency layer dedicatedto MBMS transmission. Therefore, in Embodiment 18, when the user of amobile terminal has an intention of receiving an MBMS service in thefrequency layer dedicated to MBMS transmission, the mobile terminalneeds to carryout a re-tune operation of searching for a frequency ofthe receivable frequency layer dedicated to MBMS transmission in around-robin manner to check to see whether or not the service which theuser desires is ongoing. In contrast, in Embodiment 19, each mobileterminal can know a frequency of the receivable frequency layerdedicated to MBMS transmission and the service contents receivable atthe frequency before the mobile terminal changes its frequency and thenmoves to the frequency layer dedicated to MBMS transmission. Therefore,each mobile terminal does not have to carry out the processes for anyfrequency at which the service which the user desires is not ongoing,i.e., the processes of step ST3704 and the subsequent steps in FIG. 85.Thus, in Embodiment 19, each mobile terminal does not have to search fora receivable frequency dedicated to MBMS transmission in a round-robinmanner when the user of the mobile terminal has an intention ofreceiving an MBMS service in the frequency layer dedicated to MBMStransmission. As a result, there is provided an advantage of shorteninga control delay time occurring before each mobile terminal receives aservice at a frequency other than a currently-selected frequency.Accordingly, there can also be provided an advantage of achieving lowpower consumption in each mobile terminal.

Next, variant 1 of this embodiment will be explained. The serving cell,in step ST3701 of FIG. 85, transmits information about a receivable MBMSto each mobile terminal. As a concrete example of the information abouta receivable MBMS, one or more frequencies of one or more available MBMSservices, i.e., one or more frequencies of a receivable MBSFNsynchronization area (MBSFN Synchronization Area), i.e., one or morefrequencies (referred to as one or more f(MBMS) s) of a receivablefrequency layer dedicated to MBMS transmission are informed.Furthermore, service contents receivable at above-mentioned f(MBMS) canbe informed. At that time, not all the service contents receivable atf(MBMS), but the service contents currently being ongoing in an MBSFNarea having a coverage area which overlaps the coverage area of theserving cell are informed. In Embodiment 19, each mobile terminal doesnot have a function of getting to know the service contents currentlybeing ongoing in an MBSFN area having a coverage area which overlaps thecoverage area of the serving cell. Therefore, the following situationoccurs. Even in a case in which a mobile terminal is not being locatedin the coverage area of the MBSFN area in which the service which theuser of the mobile terminal desires is ongoing, the mobile terminal, instep ST3703 of FIG. 85, determines that there exists a frequency(fc(MBMS)) of the receivable frequency layer dedicated to MBMStransmission at which the service which the user of the mobile terminaldesires is ongoing, and then, in step ST3704, switches to fc(MBMS).However, because the mobile terminal is being located outside thecoverage area of the MBSFN area in which the service which the user ofthe mobile terminal desires is ongoing, there is a high possibility thatit is determined, in step ST3510, that the quality of reception of theMBSFN area (fc(MBMS)) in which the service which the user of the mobileterminal desires is ongoing is not good enough to receive.

Compared with Embodiment 19, variant 1 can provide the following furtheradvantages. Compared with Embodiment 19, in this variant 1, each mobileterminal can receive the service contents currently being ongoing in anMBSFN area having a coverage area which overlaps the coverage area ofthe serving cell, and, in step ST3703, can check to see whether it hasreceived one or more frequencies of the receivable frequency layerdedicated to MBMS transmission at which the service which the userdesires is ongoing in the MBSFN area having a coverage area whichoverlaps the coverage area of the serving cell. Therefore, thepossibility that it is determined, in step ST3510, that the quality ofreception of the MBSFN area in which the service which the user desiresis ongoing is not good enough to receive becomes low. As a result, thereis provided an advantage of shortening a control delay time occurringbefore each mobile terminal receives a service at a frequency other thana currently-selected frequency. Accordingly, there can also be providedan advantage of achieving low power consumption in each mobile terminal.

Next, variant 2 of this embodiment will be explained. In the case whichthe neighboring cell (neighboring cell) information (list)) istransmitted from the serving cell to each mobile terminal, theinformation about a receivable MBMS in a neighboring cell can betransmitted from the serving cell to each mobile terminal. Theinformation about a receivable MBMS in a neighboring cell can betransmitted at the same time when the neighboring cell information istransmitted, or can be transmitted but not at the same time when theneighboring cell information is transmitted. Because a concrete exampleof the information about a receivable MBMS is the same as that shown inEmbodiment 19, the explanation of the concrete example will be omittedhereafter. Variant 2 can provide the following advantages. A case inwhich the receive sensitivity of a neighboring cell has become good inthe unicast/mixed frequency layer, i.e., the time to carry out ahandover process is getting close will be considered. When the servicecontents which a mobile terminal is currently receiving are not includedin the information regarding a receivable MBMS in a base station whichis selected newly as a serving cell (a new serving cell: New Servingcell, i.e., a handover destination base station), the mobile terminalcan determine that the sensitivity of the reception of the service whichit is currently receiving will get worse if it continues to move. Theresult of this determination can be notified to the user through displayof it on a display unit, with an alarm, or the like. As a result, whenthe user gives a higher priority to the current reception of the MBMSservice than to the movement, the user becomes able to stop themovement, and there can be provided an advantage of enabling the user touse the mobile terminal according to the user's needs more effectively.Furthermore, when the sensitivity of the reception of the service whichthe mobile terminal is currently receiving at f1(MBMS) gets worse, ifthe same service does not exist in the information about a receivableMBMS in the serving cell, but exists at f2 (MBMS) in the informationabout a receivable MBMS in a neighboring cell, the mobile terminal cantry to carry out an operation of searching for an MBMS at f2(MBMS), orthe like. As a result, there can be provided an advantage of enablingthe user to use the mobile terminal according to the user's needs moreeffectively. This variant 2 can be applied not only to Embodiment 19 butalso to variant 1 of Embodiment 19.

Embodiment 20

In nonpatent reference 3, an event (event) which is used to inform theresults of measurements of a serving cell and a peripheral cell from amobile terminal to a network side (a base station) in the current 3GPPis explained. A measurement within the same frequency as that in aserving cell will be explained hereafter. It is disclosed that eachmobile terminal informs an event A1 to the network side (a base station)when the result of a measurement of a serving cell becomes larger than athreshold (threshold). Each mobile terminal informs an event A2 to thenetwork side (a base station) when the result of the measurement of theserving cell becomes smaller than the threshold (threshold). Each mobileterminal informs an event A3 to the network side (a base station) whenthe result of a measurement of a peripheral cell becomes larger than avalue which is an addition of an offset (offset) to the result of themeasurement of the serving cell. The event A3 is used for a handoverwithin the same frequency. There is no description about the problems tobe solved by the present invention in nonpatent reference 3.Furthermore, there is also no description of provision of two or morethresholds and two or more offsets. In addition, there is also nodescription of use of two or more thresholds and two or more offsetsproperly according to the state of each mobile terminal.

A concrete example of a sequence diagram in a case in which a mobileterminal currently receiving an MBMS service, which is transmitted via amulti-cell transmission scheme from unicast/MBMS mixed cells, carriesout a handover in a unicast/mixed frequency layer is shown in FIG. 86. Aserving cell, in step ST3801, transmits system information about theself-cell to mobile terminals being served thereby. As a concreteexample of the system information transmitted to the mobile terminals,there are a measurement period length, a discontinuous reception cyclelength, and tracking area information (TA information). The measurementperiod length is informed from the network side to the mobile terminalsbeing served thereby, and each of the mobile terminals measures a fieldintensity and so on at periods (cycles) of this period length. When theself-cell information is transmitted from the serving cell to the mobileterminals, this self-cell information is mapped onto a broadcast controlchannel (BCCH) which is a logical channel, and the broadcast controlchannel is further mapped onto a broadcast channel (BCH) which is atransport channel and this broadcast channel is mapped onto a physicalbroadcast channel (PBCH) which is a physical channel. The self-cellinformation can be alternatively mapped onto the broadcast controlchannel (BCCH) which is a logical channel, and this broadcast controlchannel can be further mapped onto a downlink shared channel (DL-SCH)which is a transport channel and the downlink shared channel can bemapped onto a physical downlink shared channel (PDSCH) which is aphysical channel.

Each of the mobile terminals, in step ST3802, receives the systeminformation about the self-cell transmitted from the serving cell. Theserving cell, in step ST3803, transmits the information about MBMSscheduling of the self-cell to the mobile terminals being servedthereby. As a concrete example of the MBMS scheduling informationtransmitted to the mobile terminals, information about MBSFN subframeallocation (MBSFN subframe allocation), etc. can be considered.Furthermore, when the MBMS scheduling information is transmitted fromthe serving cell to the mobile terminals, this MBMS schedulinginformation is mapped onto a broadcast control channel (BCCH) which is alogical channel, and the broadcast control channel is further mappedonto a broadcast channel (BCH) which is a transport channel and thisbroadcast channel is mapped onto a physical broadcast channel (PBCH)which is a physical channel. The MBMS scheduling information can bealternatively mapped onto the broadcast control channel (BCCH) which isa logical channel, and this broadcast control channel can be furthermapped onto a downlink shared channel (DL-SCH) which is a transportchannel and the downlink shared channel can be mapped onto a physicaldownlink shared channel (PDSCH) which is a physical channel. Each of themobile terminals, in step ST3804, receives the MBMS schedulinginformation of the self-cell transmitted from the serving cell.

Each of the mobile terminals, in step ST3805, checks to see whether theuser has an intention of receiving an MBMS service. When the user has anintention of receiving an MBMS service, each of the mobile terminalsmakes a transition to step ST3807. In contrast, when the user does nothave an intention of receiving an MBMS service, each of the mobileterminals ends the process. The serving cell, in step ST3806, transmitscontrol information about MBMS services to the mobile terminals. Each ofthe mobile terminals, in step ST3807, receives the control informationabout MBMS services. As a concrete example of the control informationabout MBMS services, the contents of MBMS services or the like can beconsidered. Because a concrete example of the contents of MBMS servicesis the same as that shown in Embodiment 18, the explanation of theconcrete example will be omitted hereafter. Furthermore, when thecontrol information about MBMS services is transmitted from the servingcell to the mobile terminals, this control information about MBMSservices is mapped onto a broadcast control channel (BCCH) which is alogical channel, and the broadcast control channel is further mappedonto a broadcast channel (BCH) which is a transport channel and thisbroadcast channel is mapped onto a physical broadcast channel (PBCH)which is a physical channel. The control information about MBMS servicescan be alternatively mapped onto the broadcast control channel (BCCH)which is a logical channel, and this broadcast control channel can befurther mapped onto a downlink shared channel (DL-SCH) which is atransport channel and the downlink shared channel can be mapped onto aphysical downlink shared channel (PDSCH) which is a physical channel. Asan alternative, the control information about MBMS services can bemapped onto a multicast control channel (MCCH) which is a logicalchannel, and the multicast control channel can be mapped onto amulticast channel (MCH) which is a transport channel and the multicastchannel can be mapped onto a physical multicast channel (PMCH) which isa physical channel. In the case in which the control information aboutMBMS services is mapped onto the MCCH, each of the mobile terminalsreceives data in MBSFN subframes according to the MBMS schedulinginformation (the information about MBSFN subframe allocation) receivedin step ST3804. Each of the mobile terminals, in step ST3808, determineswhether or not the service which the user desires is ongoing accordingto the control information about MBMS services received in step ST3807.When the service which the user desires is ongoing, each of the mobileterminals makes a transition to step ST3809. In contrast, when theservice which the user desires is not ongoing, each of the mobileterminals ends the process. Each of the mobile terminals, in stepST3809, starts receiving an MBMS service (an MTCH and an MCCH). Whenreceiving an MBMS service, each of the mobile terminals receives data inMBSFN subframes according to the MBMS scheduling information (theinformation about MBSFN subframe allocation) received in step ST3804.

Each of the mobile terminals, in step ST3810, determines whether or notthe current time is in a measurement period of the measurement periodlength received in step ST3802. When the current time is in ameasurement period, each of the mobile terminals makes a transition tostep ST3811. In contrast, when the current time is not in a measurementperiod, each of the mobile terminals repeats the determination of stepST3810. Each of the mobile terminals, in step ST3811, carries out ameasurement. As values which each of the mobile terminals actuallymeasures, the reference symbol received power (Reference Symbol receivedpower: RSRP) of each of the serving cell and the peripheral cell, anE-UTRA carrier received signal strength indicator (E-UTRA carrierreceived signal strength indicator: RSSI), etc. can be considered. Theinformation about the peripheral cell can be broadcast from the servingcell as peripheral cell information (list) (or referred to neighboringcell (neighboring cells) information (list)). Each of the mobileterminals, in step ST3812, judges whether or not a re-selection (a cellre-selection) of the serving cell is needed according to the result ofthe measurements in step ST3811. As an example of a criterion of thejudgment, there can be considered whether the result of the measurementof the peripheral cell exceeds a value which is an addition of an offset(offset) to the result of the measurement of the serving cell. When nore-selection is needed, each of the mobile terminals makes a transitionto step ST3810. In contrast, when a re-selection is needed, each of themobile terminals makes a transition to step ST3813. Each of the mobileterminals, in step ST3813, informs an event which is used to inform themeasurement results to the serving cell. Each of the mobile terminalsinforms an event A3, as a concrete example of the event in a case inwhich a re-selection of the serving cell is needed, to the serving cell.The serving cell, in step ST3814, receives the event A3 from each of themobile terminals. Then, the mobile communication system carries out ahandover process, and then makes a transition to step ST3815.

A base station (a new serving cell: New serving cell) which is newlyselected as the serving cell, in step 3815, transmits the systeminformation about the self-cell to mobile terminals being servedthereby, like in step ST3810. Each of the mobile terminals, in stepST3816, receives the system information about the self-cell from the newserving cell, like in step ST3802. The new serving cell, in step ST3817,transmits the MBMS scheduling information about the self-cell to themobile terminals being served thereby, like in step ST3803. Each of themobile terminals, in step ST3818, receives the information about theMBMS scheduling of the self-cell from the new serving cell, like in stepST3804. The new serving cell, in step ST3819, transmits the controlinformation about MBMS services to the mobile terminals, like in stepST3806. Each of the mobile terminals, in step ST3820, receives thecontrol information about MBMS services, like in step ST3807. Each ofthe mobile terminals, in step ST3821, determines whether or not theservice which the user desires is ongoing according to the controlinformation about MBMS services received in step ST3820, like in stepST3808. When the service which the user desires is ongoing, each of themobile terminals makes a transition to step ST3822. In contrast, whenthe service which the user desires is not ongoing, each of the mobileterminals makes a transition to step ST3823. Each of the mobileterminals, in step ST3822, starts receiving the MBMS service (an MTCHand an MCCH) according to the MBMS scheduling information (theinformation about MBSFN subframe allocation) of the new serving basestation received in step ST3818. Each of the mobile terminals, in stepST3823, carries out a process of stopping the reception of the MBMSservice.

As shown in steps ST3821 and ST3823 of FIG. 86, there arises a problemthat the reception of the MBMS service is interrupted by a handover. Inthis Embodiment 20, a solution of the above-mentioned problem will beprovided by adding the service contents of MBMS services to theneighboring cell information. A detailed method will be explained withreference to FIG. 87. Because FIG. 87 is similar to FIG. 86, theexplanation of the same portion will be omitted. The serving cell, instep ST3901, transmits the neighboring cell information to mobileterminals being served thereby. The service contents of MBMS services ina neighboring cell is newly disposed in the neighboring cellinformation. Because a concrete example of the service contents is thesame as that shown in Embodiment 18, the explanation of the concreteexample will be omitted hereafter. Instead of the MBMS service contentsof the neighboring cell, the information about MBSFN subframe allocationof the neighboring cell can be provided. If the MBSFN subframeallocation of the neighboring cell is the same as that of the servingcell, it can be determined that the neighboring cell and the servingcell carry out multi-cell transmission of the MBMS service in order tosupport SFN combining. This is because it can be therefore determinedthat the neighboring cell and the serving cell are carrying out the sameMBMS service. Furthermore, when transmitting the neighboring cellinformation from the serving cell to the mobile terminals, theneighboring cell information is mapped onto a broadcast control channel(BCCH) which is a logical channel, and the broadcast control channel isfurther mapped onto a broadcast channel (BCH) which is a transportchannel and this broadcast channel is mapped onto a physical broadcastchannel (PBCH) which is a physical channel. The neighboring cellinformation can be alternatively mapped onto the broadcast controlchannel (BCCH) which is a logical channel, and this broadcast controlchannel can be further mapped onto a downlink shared channel (DL-SCH)which is a transport channel and the downlink shared channel can bemapped onto a physical downlink shared channel (PDSCH) which is aphysical channel.

The serving cell, in step ST3806, can transmit the service contents ofeach neighboring cell as the control information about MBMS services,instead of adding the service contents of MBMS services to theneighboring cell information. In this case, it is necessary to informthe service contents of each neighboring cell in a form corresponding toits neighboring cell number (ID). The information which is referred toas the “service contents of MBMS services currently being ongoing in theneighboring cells” is transmitted via a multi-cell transmission schemefrom unicast/MBMS mixed cells in the unicast/mixed frequency layer. Theinformation is the parameter newly disposed in this Embodiment 20 inorder to solve the problem of interruption of MBMS reception whicharises when a mobile terminal currently receiving an MBMS servicecarries out a handover. Therefore, the parameter is effective only forsuch a mobile terminal currently receiving an MBMS service. Therefore,there is no problem even if the service contents of MBMS services areadded to the control information about MBMS services which only a mobileterminal currently receiving an MBMS service receives. As a result, theincrease in the amount of information of the BCCH can be prevented, andthere can be provided an advantage of preventing a control delay timefrom occurring in the whole mobile communication system. In addition,each of the mobile terminals can receive and decode the service contentsof each neighboring cell added to the control information about MBMSservices after the mobile terminal actually starts receiving the MBMSservice in step ST3809. In this case, there is an issue of how theserving cell acquires the service contents of each neighboring cell. Asa solution, there can be considered a case in which the service contentsare informed by using communications between base stations, that is,each neighboring cell informs its service contents to the serving cell.As another solution, there can be considered a case in which each cellinforms the service contents to an MME, and the MME then informs theservice contents of each cell included in the neighboring cells to theserving cell. As another solution, there can be considered a case inwhich an MCE informs the service contents of each cell to an MME, andthe MME informs the service contents of each cell included in theneighboring cells to the serving cell. As another solution, there can beconsidered a case in which an MCE informs the service contents of eachneighboring cell directly to each serving cell. Each of the mobileterminals, in step ST3902, receives the neighboring cell information.

Each of the mobile terminals, in step ST3903, checks the servicecontents of MBMS services of each neighboring cell, and determineswhether or not the service which the mobile terminal is currentlyreceiving is ongoing in the new serving cell. When the service isongoing in the new serving cell, each of the mobile terminals makes atransition to step ST3813. In contrast, when the service is not ongoingin the new serving cell, each of the mobile terminals makes a transitionto step ST3904. Each of the mobile terminals, in step ST3904, does notinform the event which is used for notification of the measurementresult to the serving cell. Concretely, each of the mobile terminalsdoes not inform the event in the case in which a re-selection of theserving cell is needed. More concretely, each of the mobile terminalsdoes not inform the event A3 to the serving cell. As a result, themobile communication system does not start the handover process, anddoes not carry out a re-selection of the serving cell. Therefore, therecan be provided an advantage of preventing the previously-selectedserving cell in which the MBMS service which the user desires is ongoingfrom being changed, thereby preventing the MBMS service reception frombeing interrupted. As a result, the problem of an interruption of MBMSservice reception occurring in a mobile terminal currently receiving anMBMS service transmitted via a multi-cell transmission scheme from MBMSdedicated cells or unicast/MBMS mixed cells in a unicast/mixed frequencylayer due to occurrence of a handover, which is to be solved by thepresent invention, can be solved.

Furthermore, because it is a fact that each of the mobile terminals, instep ST3812, may judge that a re-selection (a cell re-selection) of theserving cell is needed according to the results of the measurements instep ST3811, the user should stop the movement if he or she does notwant to interrupt the MBMS service reception. Therefore, when each ofthe mobile terminals has stopped the handover process because thedesired MBMS service is not ongoing in the new serving cell in spite ofhaving determined that a re-selection of the serving cell is needed, anotification to the effect can be sent to the user through display of iton a display unit, with an alarm, or the like. As a result, when theuser gives a higher priority to the current reception of the MBMSservice than to the movement, the user becomes able to stop themovement, and there can be provided an advantage of enabling the user touse the mobile terminal according to the user's needs more effectively.Each of the mobile terminals, in step ST3904, instead of not informingthe event A3 to the serving cell, can inform the user's intention to theserving cell while informing the event (event A3) in the case in which are-selection of the serving cell is needed to the serving cell. As aconcrete example of the user's intention, a desire for non-execution ofa handover can be considered.

In accordance with Embodiment 20, the problem of an interruption of MBMSservice reception occurring in a mobile terminal currently receiving anMBMS service transmitted via a multi-cell transmission scheme fromunicast/MBMS mixed cells in a unicast/mixed frequency layer due tooccurrence of a handover, which is to be solved by the presentinvention, can be solved.

Embodiment 21

A sequence diagram of a mobile communication system which is used inEmbodiment 21 is shown in FIG. 88. In FIG. 88, because the same steps asthose shown in FIG. 86 denote the same processes as those shown in thefigure or like processes, the explanation of the steps will be omittedhereafter. A serving cell, in step ST4001, transmits system informationabout the self-cell to mobile terminals being served thereby. As aconcrete example of the system information transmitted to the mobileterminals, there are a measurement period length, a discontinuousreception cycle length, and tracking area information (TA information).The measurement period length is informed from the network side to themobile terminals being served by the cell, and each of the mobileterminals measures a field intensity and so on at periods (cycles) ofthis period length. Measurement reporting parameters (measurementreporting parameters) which are used at the time of measurements of theserving cell and a peripheral cell are included in the systeminformation about the self-cell. As a concrete example of themeasurement reporting parameters, a “threshold (threshold)”, an “offset(offset)”, etc., which are shown in nonpatent reference 3, can beconsidered. In this Embodiment 21, it is newly considered that theabove-mentioned measurement reporting parameters are divided intoparameters for mobile terminals each of which is not receiving an MBMSservice transmitted via a multi-cell transmission scheme fromunicast/MBMS mixed cells in a unicast/mixed frequency layer (simplyreferred to as MBMS service non-receiving mobile terminals from hereon), and parameters for mobile terminals each of which is receiving anMBMS service transmitted via a multi-cell transmission scheme fromunicast/MBMS mixed cells in a unicast/mixed frequency layer (simplyreferred to as MBMS service receiving mobile terminals from here on). Inaddition, it is considered that the offset is divided into an offset forMBMS service non-receiving mobile terminals and an offset for MBMSservice receiving mobile terminals. Furthermore, it is considered thatthe offset for MBMS service receiving mobile terminals is made to belarger than that for MBMS service non-receiving mobile terminals.

When the self-cell information is transmitted from the serving cell tothe mobile terminals, the self-cell information is mapped onto abroadcast control channel (BCCH) which is a logical channel, and thebroadcast control channel is further mapped onto a broadcast channel(BCH) which is a transport channel and this broadcast channel is mappedonto a physical broadcast channel (PBCH) which is a physical channel.The self-cell information can be alternatively mapped onto the broadcastcontrol channel (BCCH) which is a logical channel, and this broadcastcontrol channel can be further mapped onto a downlink shared channel(DL-SCH) which is a transport channel and the downlink shared channelcan be mapped onto a physical downlink shared channel (PDSCH) which is aphysical channel. The “measurement reporting parameters” for MBMSservice receiving mobile terminals are established newly in order tosolve the problem that when a mobile terminal which is receiving an MBMSservice transmitted via a multi-cell transmission scheme fromunicast/MBMS mixed cells in a unicast/mixed frequency layer carries outa handover, an MBMS receive interruption can occur. Therefore, theparameters are effective for a mobile terminal which is receiving anMBMS service. Therefore, there is no problem even if the parameters areseparated from the other system information and are added to the controlinformation about MBMS services received by a mobile terminal whichreceives an MBMS service. As a result, the increase in the amount ofinformation of the BCCH can be prevented, and there can be provided anadvantage of preventing a control delay time from occurring in the wholemobile communication system. When the control information about MBMSservices is transmitted from the serving cell to the mobile terminals,this control information about MBMS services is mapped onto a broadcastcontrol channel (BCCH) which is a logical channel, and the broadcastcontrol channel is further mapped onto a broadcast channel (BCH) whichis a transport channel and this broadcast channel is mapped onto aphysical broadcast channel (PBCH) which is a physical channel. Thecontrol information about MBMS services can be alternatively mapped ontothe broadcast control channel (BCCH) which is a logical channel, andthis broadcast control channel can be further mapped onto a downlinkshared channel (DL-SCH) which is a transport channel and the downlinkshared channel can be mapped onto a physical downlink shared channel(PDSCH) which is a physical channel. As an alternative, the controlinformation about MBMS services can be mapped onto a multicast controlchannel (MCCH) which is a logical channel, and the multicast controlchannel can be mapped onto a multicast channel (MCH) which is atransport channel and the multicast channel can be mapped onto aphysical multicast channel (PMCH) which is a physical channel. Each ofthe mobile terminals, in step ST4002, receives the system informationabout the self-cell from the serving cell.

Each of the mobile terminals, in step ST4003, determines whether or notit is receiving an MBMS. Concretely, each of the mobile terminalsdetermines whether or not it is receiving an MBMS service transmittedvia a multi-cell transmission scheme from unicast/MBMS mixed cells in aunicast/mixed frequency layer. When each of the mobile terminals isreceiving an MBMS, the mobile terminal makes a transition to stepST4004. In contrast, when each of the mobile terminals is not receivingan MBMS, the mobile terminal makes a transition to step ST4005. Each ofthe mobile terminals, in step ST4004, sets the measurement reportingparameters for MBMS receiving mobile terminals to its measurementreporting parameters. Concretely, each of the mobile terminals sets theoffset for MBMS receiving mobile terminals to its offset. Each of themobile terminals, in step ST4005, sets the measurement reportingparameters for MBMS non-receiving mobile terminals to its measurementreporting parameters. More concretely, each of the mobile terminals setsthe offset for MBMS non-receiving mobile terminals to its offset.

In accordance with this Embodiment 21, it becomes able to change theresults of measurements of a peripheral cell (a new serving cell) inwhich a handover process occurs in a mobile terminal currently receivingan MBMS service and a mobile terminal not receiving an MBMS service.Furthermore, by making the offset for MBMS service receiving mobileterminals be larger than the offset for MBMS service non-receivingmobile terminals, the result of the measurement of the peripheral cellin which an MBMS service receiving mobile terminal carries out ahandover process can be made to be higher than that of the measurementof the peripheral cell in which an MBMS service non-receiving mobileterminal carries out a handover process. As a result, the possibilitythat a handover occurs in a mobile terminal which is receiving an MBMSservice transmitted via a multi-cell transmission scheme fromunicast/MBMS mixed cells in a unicast/mixed frequency layer can bereduced compared with the possibility that a handover occurs in a mobileterminal which is not receiving an MBMS service transmitted via amulti-cell transmission scheme from the unicast/MBMS mixed cells in theunicast/mixed frequency layer when they are geographically located atthe same location. Accordingly, a geographical area in which each mobileterminal can receive an MBMS service transmitted via a multi-celltransmission scheme from the unicast/MBMS mixed cells in theunicast/mixed frequency layer from an identical base station can bewidened. As a result, there can be provided an advantage of reducing theoccurrence of an interruption of MBMS service reception in a mobileterminal which is receiving an MBMS service transmitted via a multi-celltransmission scheme from unicast/MBMS mixed cells in a unicast/mixedfrequency layer due to occurrence of a handover. In Embodiment 20, theproblem is solved by newly adding the service contents of MBMS servicesof a neighboring cell to the neighboring cell information. However, itcan be expected that the amount of information of the service contentsof MBMS services of each neighboring cell increases. In this Embodiment21, the problem is solved without adding the service contents of MBMSservices of a neighboring cell. Therefore, the problem can be solvedwhile reducing the amount of information transmitted from the servingcell to each mobile terminal as compared with Embodiment 20. Therefore,there can be provided an advantage of making further effective use ofthe radio resources as compared with Embodiment 20.

Next, variant 1 of this embodiment will be explained. By modifyingEmbodiment 21 as follows, a further advantage can be provided. Asequence diagram of a mobile communication system which is used invariant 1 of Embodiment 21 is shown in FIG. 89. In FIG. 89, because thesame steps as those shown in FIG. 86 or 88 denote the same processes asthose shown in the figure or like processes, the explanation of thesteps will be omitted hereafter. Each of the mobile terminals, in stepST4003, determines whether or not it is receiving an MBMS. Moreconcretely, each of the mobile terminals determines whether or not it isreceiving an MBMS service transmitted via a multi-cell transmissionscheme from unicast/MBMS mixed cells in a unicast/mixed frequency layer.When each of the mobile terminals is receiving an MBMS, the mobileterminal makes a transition to step ST4101. In contrast, when each ofthe mobile terminals is not receiving an MBMS, the mobile terminal makesa transition to step ST4005. Each of the mobile terminals, in stepST4101, checks the user's intention. More concretely, each of the mobileterminals determines whether to give a higher priority to MBMS servicereception than to unicast communications. More concretely, each of themobile terminals determines whether to give priority to reception of anMBMS service transmitted via unicast communications and via a multi-celltransmission scheme from unicast/MBMS mixed cells in a unicast/mixedfrequency layer. When each of the mobile terminals gives priority toreception of an MBMS service, the mobile terminal makes a transition tostep ST4004. In contrast, when each of the mobile terminals does notgive priority to reception of an MBMS service, the mobile terminal makesa transition to step ST4005.

Variant 1 of Embodiment 21 can provide the following further advantages.In the case in which each of the mobile terminals, in step ST4004, setsthe offset for MBMS receiving mobile terminals to its offset, even if amobile terminal which is not receiving an MBMS service starts a handoverprocess of performing a handover to a new serving cell because itsreceiving state of receiving data from the current serving cell getsworse (even if the mobile terminal informs an event A3 to the servingcell), a mobile terminal currently receiving an MBMS service does notstart a handover process even in the same receiving state (in otherwords, at the same geographical location). This means that a mobileterminal currently receiving an MBMS service stays at the currentserving cell even in a case in which a mobile terminal which is notreceiving an MBMS service starts a handover process by determining thatits receiving state of receiving data from the current serving cell isbad. Therefore, although an interruption of MBMS service reception doesnot occur in a mobile terminal currently receiving an MBMS service,there may be a case in which such a situation results in degradation inthe quality of reception of a unicast service. Therefore, by using thisvariant, the processing carried out by the mobile communication systemcan be made to reflect the user's intention of either preventingoccurrence of interruptions of MBMS service reception as much aspossible, or allowing interruptions of MBMS service reception to preventthe degradation of the quality of reception of a unicast service, andtherefore there can be provided an advantage of enabling the user to usehis or her mobile terminal according to the user's needs moreeffectively.

Next, variant 2 of this embodiment will be explained. By modifyingEmbodiment 21 as follows, a further advantage can be provided. Asequence diagram of a mobile communication system which is used invariant 2 of Embodiment 21 is shown in FIG. 90. In FIG. 90, because thesame steps as those shown in FIGS. 86 to 40 denote the same processes asthose shown in the figure or like processes, the explanation of thesteps will be omitted hereafter. Each of the mobile terminals, in stepST4003, determines whether or not it is receiving an MBMS. When each ofthe mobile terminals is receiving an MBMS, the mobile terminal makes atransition to step ST4201. In contrast, when each of the mobileterminals is not receiving an MBMS, the mobile terminal makes atransition to step ST4005. Each of the mobile terminals, in step ST4201,checks the service contents of MBMS services of a neighboring cell byusing neighboring cell information received in step ST3902, as to aperipheral cell which is a measurement object. As to a peripheral cellwhich is a measurement object, each of the mobile terminals determineswhether or not an MBMS service which it is receiving is ongoing in thecurrent serving cell. When an MBMS service which each of the mobileterminals is receiving is ongoing in the current serving cell, themobile terminal makes a transition to step ST4005. In contrast, when anMBMS service which each of the mobile terminals is receiving is notongoing in the current serving cell, the mobile terminal makes atransition to step ST4004.

Variant 2 of Embodiment 21 can provide the following further advantages.In a case in which an MBMS service which a mobile terminal is receivingin the current serving cell is ongoing in the new serving cell, theproblem of an interruption of MBMS service reception due to occurrenceof a handover does not arise. Therefore, in the case in which an MBMSservice which a mobile terminal is receiving in the current serving cellis ongoing in the new serving cell, it becomes able to prevent the useof measurement reporting parameters for MBMS service receiving mobileterminals resulting in degradation of the quality of reception of aunicast service (including an MBMS service). Furthermore, variant 1 andvariant 2 of Embodiment 21 can be used in combination.

Embodiment 22

A case in which radio resources which base stations belonging to allMBSFN areas in an MBSFN synchronization area use for multi-celltransmission from a unicast/MBMS mixed cell in a unicast/mixed frequencylayer is made to be identical to one another will be considered. Moreconcretely, it will be considered that each of all the MBSFN areas inthe MBSFN synchronization area use MBSFN subframes which are used fortransmission of an MBMS service (an MCCH and an MTCH). Morespecifically, radio resources (MBSFN subframes) common in the MBSFNsynchronization area are used in such a way that the radio resources aremultiplexed in each of the MBSFN areas. Concrete examples of amultiplexing method are shown in FIG. 91. FIG. 91 is an explanatorydrawing showing a concept underlying the method of multiplexing MBSFNsubframes in each of the MBSFN areas. In FIG. 91, A shows “MBMS servicedata from a base station belonging to an MBSFN area A”, and B shows“MBMS service data from a base station belonging to an MBSFN area B”. InFIG. 91(A) (a pattern A), time division multiplexing of radio resources(MBSFN subframes) which the base station belonging to the MBSFN area Aand the base station belonging to the MBSFN area B use is carried out.Within each MBSFN subframe, a time period during which the base stationbelonging to the MBSFN area A transmits an MBMS service is the oneduring which the base station belonging to the MBSFN area B does notcarry out transmission of an MBMS service and a unicast service, i.e.,the transmission is in an off state. Furthermore, a time period duringwhich the base station belonging to the MBSFN area B transmits an MBMSservice is the one during which the base station belonging to the MBSFNarea A does not carry out transmission of an MBMS service and a unicastservice, i.e., the transmission is in an off state. Although a pattern Bshows a concrete example of time division multiplexing, in the patternB, each MBSFN subframe is not time-divided, but an MBSFN subframe whichis used for each MBSFN area is determined. Also in FIG. 91(B) (thepattern B), within an MBSFN subframe via which the base stationbelonging to the MBSFN area A transmits an MBMS service, the basestation belonging to the MBSFN area B does not carry out transmission ofan MBMS service and a unicast service, i.e., the transmission is in anoff state, like in the case of the pattern A. Furthermore, within anMBSFN subframe via which the base station belonging to the MBSFN area Btransmits an MBMS service, the base station belonging to the MBSFN areaA does not carry out transmission of an MBMS service and a unicastservice, i.e., the transmission is in an off state.

In FIG. 91(C) (a pattern C), an example in which frequency divisionmultiplexing (FDM: Frequency Division Multiplexing) of radio resources(MBSFN subframes) which the base station belonging to the MBSFN area Aand the base station belonging to the MBSFN area B use is carried out isshown. Within each MBSFN subframe, at a frequency at which the basestation belonging to the MBSFN area A transmits an MBMS service, thebase station belonging to the MBSFN area B does not carry outtransmission of an MBMS service and a unicast service, i.e., thetransmission is in an off state. Within each MBSFN subframe, at afrequency at which the base station belonging to the MBSFN area Btransmits an MBMS service, the base station belonging to the MBSFN areaA does not carry out transmission of an MBMS service and a unicastservice, i.e., the transmission is in an off state. In FIG. 91(D) (apattern D), an example in which code division multiplexing of radioresources (MBSFN subframes) which the base station belonging to theMBSFN area A and the base station belonging to the MBSFN area B use iscarried out is shown. With the radio resources (each MBSFN subframe)common in the MBSFN synchronization area, the base station belonging tothe MBSFN area A multiplies data by a code A and transmits an MBMSservice. Furthermore, with the radio resources (each MBSFN subframe)common in the MBSFN synchronization area, the base station belonging tothe MBSFN area B multiplies data by a code B and transmits an MBMSservice. The example in which base stations belonging to all MBSFN areasin an MBSFN area use identical radio resources (MBSFN subframes) isdescribed above. As an alternative, base stations which construct anMBSFN area and base stations belonging to a neighboring MBSFN area canuse identical radio resources.

In accordance with Embodiment 22, there can be provided an advantage ofreducing the occurrence of an interruption of MBMS service reception ina mobile terminal which is receiving an MBMS service transmitted via amulti-cell transmission scheme from unicast/MBMS mixed cells in aunicast/mixed frequency layer due to occurrence of a handover. This isbecause in the mobile communication system as shown in Embodiment 22,base stations belonging to an MBSFN synchronization area provide MBMSservices by using identical radio resources (MBSFN subframes). A case inwhich the current serving cell belongs to the MBSFN area A, and the newserving cell belongs to the MBSFN area B will be considered. In the caseof a unicast service, each mobile terminal carries out transmission andreception with the new serving cell having good quality of reception,and the new serving cell carries out scheduling. In contrast, in thecase of an MBMS service, each mobile terminal can receive an MBMSservice in an MBSFN area in which a service that the user of the mobileterminal desires is ongoing. Furthermore, because an MBMS service istargeted for a base station belonging to an MBSFN synchronization area,it is not necessary to newly add base stations among whichsynchronization is established in order to implement this embodiment andtherefore the complexity of the mobile communication system is notincreased. Compared with Embodiment 20, the following advantages can beprovided. The service contents of MBMS services of a neighboring cellwhich are needed in Embodiment 20 become unnecessary. Therefore,compared with Embodiment 20, the problem can be solved while the amountof information transmitted from the serving cell to each mobile terminalis reduced. Therefore, compared with Embodiment 20, there can beprovided an advantage of making effective use of the radio resources.

Compared with Embodiment 21, the following advantages can be provided.The measurement reporting parameters which are divided into the ones formobile terminals each of which is not receiving an MBMS servicetransmitted via a multi-cell transmission scheme from unicast/MBMS mixedcells in a unicast/mixed frequency layer, and the ones for mobileterminals each of which is receiving an MBMS service transmitted via amulti-cell transmission scheme from unicast/MBMS mixed cells in aunicast/mixed frequency layer, and which are needed in Embodiment 21,become unnecessary. Therefore, compared with Embodiment 21, the problemcan be solved while the amount of information transmitted from theserving cell to each mobile terminal is reduced. Therefore, comparedwith Embodiment 21, there can be provided an advantage of makingeffective use of the radio resources. Furthermore, in accordance withEmbodiment 22, because even a mobile terminal currently receiving anMBMS service becomes able to carry out a handover regardless of whetherthe MBMS service which the mobile terminal is receiving is ongoing inthe new serving cell when its quality of reception of data from thecurrent serving cell is reduced by the same degree as that of a mobileterminal not receiving the MBMS service, there can be provided anadvantage of preventing degradation in the quality of reception of aunicast service compared with Embodiment 21.

Embodiment 23

A problem to be solved by this invention will be explained withreference to FIG. 92. A shown in FIG. 92 denotes an L1/L2 signalingchannel, and B shown in FIG. 92 denotes a resource for unicasttransmission. Allocation of MBSFN subframes in an MBMS/unicast-mixedcell has been studied as disclosed in nonpatent reference 2.Multiplexing of a channel used for MBSFN (Multimedia Broadcast multicastservice Single Frequency Network) and a channel used for other thanMBSFN is carried out for each subframe, as disclosed in nonpatentreference 1. Hereafter, a subframe used for MBSFN transmission isreferred to as an MBSFN subframe (MBSFN subframe). In the current 3GPP,it is determined that a mixed cell must not use one or two leading OFDMsymbols of each subframe for unicast transmission in an MBSFN frame(subframe). In other words, anything other than one or two leading OFDMsymbols is a resource dedicated to MBMS transmission. In FIG. 92, thisresource is expressed as a PMCH. On the other hand, nonpatent reference1 discloses that a PCH is mapped onto a PDSCH or a PDCCH. Nonpatentreference 1 also discloses that a paging group uses an L1/L2 signalingchannel (PDCCH) and that a precise identifier (UE-ID) of a mobileterminal can be found on a PCH. Therefore, because a PCH uses an L1/L2signaling channel, even an MBSFN frame can be mapped onto the PCH. Onthe other hand, in a case in which allocation of a downlink radioresource to the next control information using the PCH is carried out inan MBSFN frame, because a downlink radio resource on an identicalsubframe is used exclusively for MBMS transmission, there arises aproblem that the control information cannot be allocated to theidentical subframe.

Nonpatent reference 4 has the following description on transmission of apaging signal to a mobile terminal. A PICH (Paging Indicator channel)showing that a paging signal destined for a mobile terminal belonging toa paging group is occurring is transmitted by using an L1/L2 signalingchannel. In order to determine whether or not the paging signal is theone destined therefor, the mobile terminal decodes the paging signal. APCH can have one or more paging signals. The PICH is transmitted byusing an L1/L2 signaling channel. In other words, the PICH is positionedat one to three leading OFDM symbols of each subframe. On the otherhand, the PCH is mapped onto a PDSCH in the same subframes as those atwhich the PICH is positioned. The problem to be solved by the presentinvention also arises in the paging signal transmitting proceduredisclosed in nonpatent reference 4. That is, in a case in which MBSFNsubframes are formed in an MBMS/unicast-mixed cell, the same subframesas those at which the PICH is positioned are a resource dedicated toMBMS transmission even if the PICH is transmitted with the one or twoleading OFDM symbols of each of the MBSFN subframes. Therefore, it isimpossible to transmit the PCH onto which a paging signal for enablingeach mobile terminal to determine whether or not the paging signal isdestined therefor is mapped. There is also no suggestion about theproblem to be solved by the present invention in nonpatent reference 4.

Nonpatent reference 5 has the following description about an equationused for determining a time when paging occurs (i.e., paging occasion:Paging occasion). This reference describes that in order to determine apaging occasion, two parameters: a paging interval length (correspondingto a discontinuous reception cycle length in a mixed frequency layer inaccordance with the present invention), and the number of pagingoccasions during the paging interval are needed, and there are no othernecessary parameters. Furthermore, the reference describes that asubframe in a radio frame in which a paging occasion occurs has a fixedvalue. However, nonpatent reference 5 has no description about a methodof determining a subframe in a radio frame for paging occasion ontowhich a paging signal is mapped. Furthermore, nonpatent reference 5 hasno description about a relation between a subframe in a radio frame forpaging occasion and an MBSFN subframe, and there is also no suggestionabout the problem to be solved by the present invention.

OFDM symbols other than the one or two leading OFDM symbols of eachMBSFN subframe are a resource dedicated to MBMS transmission. In a casein which the subframe in a radio frame for paging occasion coincideswith MBSFN subframe allocation, any OFDM symbols other than the one ortwo leading OFDM symbols of the subframe are a resource dedicated toMBMS transmission and cannot be used for paging processing. BecauseMBSFN subframes are not taken into consideration at all in theconventional paging processing method, there arises a problem that it isimpossible to apply the conventional paging processing method to pagingprocessing in an MBMS/unicast-mixed cell. In order to solve thisproblem, in this Embodiment 23, a method of determining which subframein a radio frame for paging occasion is used for the paging process(transmission of a paging signal (a paging message), a PICH, a PCH,etc.) will be disclosed. A concrete example of a sequence diagram in acase of determining a subframe in a radio frame for paging occasion ontowhich a paging signal is mapped is shown in FIG. 93. Because processesin the same step numbers as those shown in FIG. 88 are the same as thoseshown in the figure, the explanation of the processes will be omitted. Aserving cell, in step ST4001, transmits system information about theself-cell to mobile terminals being served thereby. As a concreteexample of the system information transmitted to the mobile terminals,there are a measurement period length, a discontinuous reception cyclelength, and tracking area information (TA information). A parameter fordiscontinuous reception is included in the system information about theself-cell. As a concrete example of the parameter for discontinuousreception, a discontinuous reception cycle length (T) in a mixedfrequency layer, the number (N) of paging occasions within a paginginterval (or the number of paging groups), etc. are provided. As aconcrete example of the indication of the discontinuous reception cyclelength, the number of radio frames can be used. Each mobile terminal, instep ST4002, receives the system information about the self-cell fromthe serving cell. The serving cell, in step ST4501, transmitsinformation about allocation of MBSFN subframes. In the debate in thecurrent 3GPP regarding MBSFN subframe allocation, the following pointshave been discussed. The mapping position of a reference signal in anMBSFN subframe as a radio resource differs from that of a referencesignal in a subframe which is not an MBSFN subframe as a radio resource.It has been debated that in order to carry out a more correctmeasurement using a reference signal, even a mobile terminal having nocapability of receiving an MBMS service needs to grasp the informationabout MBSFN subframe allocation in the serving cell (nonpatent reference2). As a concrete example of the information about MBSFN subframeallocation, the subframe number of a subframe allocated as an MBSFNsubframe (e.g., in FIG. 92, subframe number #1) can be considered. Eachmobile terminal, in step ST4502, receives the information aboutallocation of MBSFN subframes from the serving cell.

Each mobile terminal, in step ST4503, determines a paging occasion. Inthis Embodiment 23, a determining method of determining a subframe in aradio frame for paging occasion to solve the problem will be disclosed.The method disclosed in this Embodiment 23 can be used regardless of amethod of determining a paging occasion (a radio frame for pagingoccasion). The serving cell, in step ST4504, determines a radio framefor paging occasion by using the same method as that which each mobileterminal uses, as the mobile communication system. Each mobile terminal,in step ST4505, determines a subframe in a radio frame for pagingoccasion. The serving cell, in step ST4506, determines a subframe in aradio frame for paging occasion by using the same method as that whicheach mobile terminal uses, as the mobile communication system.

The details of the method of determining a subframe in a radio frame ofpaging occasion in step ST4505 will be explained hereafter. Each mobileterminal determines subframes other than subframes which can be MBSFNsubframes as subframes in a radio frame for paging occasion on the basisof the information about MBSFN subframe allocation received in stepST4502. More concretely, each mobile terminal re-numbers the subframesexcluding subframes which can be MBSFN subframes. The renumbering willbe explained with reference to FIG. 94. In FIG. 94, A denotes an MBSFNsubframe. FIG. 94(a) shows a radio frame in which no MBSFN subframeexists. FIG. 94(b) shows an example of the re-numbering of the subframeswhen an MBSFN subframe is allocated to subframe number #3, for example.The following correspondence between the yet-to-be-renumbered subframenumbers and the renumbered subframe numbers is provided.

(yet-to-be-renumbered subframe number−renumbered subframe number)

(#0-#0 (MBSFN))

(#1-#1 (MBSFN))

(#2-#2 (MBSFN))

(#3-MBSFN subframe)

(#4-#3 (MBSFN))

(#5-#4 (MBSFN))

(#6-#5 (MBSFN))

(#7-#6 (MBSFN))

(#8-#7 (MBSFN))

(#9-#8 (MBSFN))

Hereinafter, each renumbered subframe number is shown while being addedwith (MBSFN). In FIG. 94(c), a case in which two MBSFN subframes areallocated to one radio frame is shown. Because the details of therenumbering is the same as that in the case in which the number of MBSFNsubframes is one, the explanation of the details of the renumbering willbe omitted hereafter. A subframe in a radio frame for paging occasion isdetermined while being brought into correspondence with the number ofsubframes excluding subframes which can be MBSFN subframes. Acorrespondence table is shown in FIG. 95 as a concrete example. FIG.95(a) will be explained. When the number of subframes excludingsubframes which can be MBSFN subframes is “9” (that is, one subframe isallocated as an MBSFN subframe in this radio frame), #4(MBSFN) isdetermined as a subframe in a radio frame for paging occasion.Determination of a subframe in a radio frame for paging occasion usingFIG. 95(a) in the case of FIG. 94(c) will be shown. In the case of FIG.94(c), the number of subframes excluding subframes which can be MBSFNsubframes is “8”. When a subframe in a radio frame for paging occasionis determined by using FIG. 95(a), #3 (MBSFN) is obtained. Acorrespondence table taking into consideration a case in which two ormore subframes occurs in one radio frame for paging occasion is shown inFIG. 95(b).

For example, in a case in which the number of subframes occurring in oneradio frame for paging occasion shown in FIG. 95(b) is “2”, each mobileterminal cannot determine which one of the two subframes, which is shownin the column corresponding to the case in which the number of subframesoccurring in one radio frame for paging occasion shown in FIG. 95(b) is“2”, the mobile terminal itself should receive (monitor) viadiscontinuous reception. This problem can be solved by using thefollowing method. (The identifier of each mobile terminal mod the numberof subframes for paging occasion in one radio frame) is determined. Whenthe number of subframes for paging occasion in one radio frame is “2”,the solution of the above-mentioned equation is 0 or 1. Therefore, as aconcrete example, when the solution of the above-mentioned equation is“0”, the subframe number on the upper side of the correspondence tableis specified, whereas when the solution of the above-mentioned equationis “1”, the subframe number on the lower side of the correspondencetable is specified. As an alternative, the above-mentioned informationcan be included in the correspondence table. As another solution, eachmobile terminal receives (monitors) all of the plurality of subframesfor paging occasion existing in one radio frame. As a result, theabove-mentioned problem is solved. Furthermore, there can occur a casein which even though a plurality of paging occasions occur in one radioframe, a required number of subframe numbers for paging occasion cannotbe determined because of a relation with the MBSFN subframe allocation.More specifically, that case is the one in which the number of subframesfor paging occasion occurring in one radio frame, which is shown in FIG.95(b), is “2” and the number of subframes excluding subframes which canbe MBSFN subframes is “1”. This problem can be solved by using thefollowing method. The number of paging groups and/or the discontinuousreception cycle length (T) in the mixed frequency layer and/or the MBSFNsubframe allocation (the number of allocations) is determined in such away that the number of paging occasions existing in one radio frame isequal to or smaller than the number of subframes excluding subframeswhich can be MBSFN subframes. In other words, the number (N) of paginggroups, the discontinuous reception cycle length (T) in the mixedfrequency layer, or the number of MBSFN subframe allocations can bedetermined in such a way that the following equation is satisfied: (“thenumber (N) of paging groups/the discontinuous reception cycle length (T)in the mixed frequency layer=<10(the number of subframes in one radioframe−the number of MBSFN subframe allocations”)).

A concrete example of the above-mentioned case in which a plurality ofsubframes for paging occasion occur in one radio frame will be describedhereafter. A case in which nonpatent reference 5 is used in the methodof determining a radio frame of paging occasion will be considered. Aspreviously mentioned, it is described in nonpatent reference 5 that inorder to determine a paging occasion, two parameters including a paginginterval length (corresponding to the discontinuous reception cyclelength in the mixed frequency layer in the present invention) (T), andthe number (N) of paging occasions during a paging interval are needed,and no other parameters are needed. The case in which a plurality ofsubframes for paging occasion occur in one radio frame can be shown bythe following equation (1<N/T). A concrete example of the method ofusing FIG. 95 (b) in this case will be shown hereafter.

In the case of 1<N/T=<2, two subframes corresponding to paging occasionsof different paging groups exist in one radio frame. Therefore, in thecase of 1<N/T=<2, the column corresponding to the case in which thenumber of subframes for paging occasion occurring in one radio frame,shown in FIG. 95(b), is “2” is used.

The correspondence table as shown in FIG. 95 needs to be shared by thenetwork side and the mobile terminal side. As an alternative, thecorrespondence table can be determined statically in the mobilecommunication system. As a result, because the network side does nothave to inform the correspondence table to the mobile terminal side,there can be provided a further advantage of making effective use of theradio resources. On the other hand, if the correspondence table can bechanged, the correspondence table can be mapped onto a broadcast controlchannel (BCCH) as a logical channel, and the broadcast control channelcan be mapped onto a broadcast channel (BCH) which is a transportchannel and the broadcast channel can be mapped onto a physicalbroadcast channel (PBCH) which is a physical channel. As anotherconcrete example, the correspondence table can be alternatively mappedonto the broadcast control channel (BCCH) as a logical channel, and thisbroadcast control channel can be mapped onto a downlink shared channel(DL-SCH) which is a transport channel and the downlink shared channelcan be mapped onto a physical downlink shared channel (PDSCH) which is aphysical channel. By enabling the correspondence table to be changed,there can be provided a further advantage of being able to construct themobile communication system with flexibility.

In Embodiment 23, the subframes excluding subframes which can be MBSFNsubframes are re-numbered, and subframes in a radio frame for pagingoccasion are determined on the basis of the re-numbered subframenumbers. Therefore, the subframes in one radio frame for paging occasionand the MBSFN subframes are prevented from being identical subframes.Therefore, there can be provided an advantage of being able to solve theproblem of the present invention.

In this variant 1, a different method for use in the process of stepST4505 of Embodiment 23 will be shown. Each mobile terminal makes thesubframes excluding subframes which can be MBSFN subframes be thesubframes in a radio frame for paging occasion on the basis of theinformation about MBSFN subframe allocation received in step ST4502.More concretely, each mobile terminal renumbers the subframes excludingsubframes which can be MBSFN subframes. Because the details of therenumbering is the same as that shown in Embodiment 23, the explanationof the details of the renumbering will be omitted hereafter. In thisvariant 1, it will be considered that instead of the correspondencetable, a relation between the number of subframes excluding subframeswhich can be MBSFN subframes and the subframes in a radio frame forpaging occasion is maintained constant, unlike in Embodiment 23. Inother words, an expression showing the relation between the number ofsubframes excluding subframes which can be MBSFN subframes and thesubframes in a radio frame for paging occasion is defined. Concreteexamples of the expression showing the relation will be shown hereafter.

An identifier of each mobile terminal (UE-ID, IMSI, S-TMSI, or the like)mod (the number of subframes excluding subframes which can be MBSFNsubframes)=the subframes in a radio frame for paging occasion (wherethey have the re-numbered subframe numbers) (equation 1), and

(an identifier of each mobile terminal (UE-ID, IMSI, S-TMSI, or thelike) div the number of paging groups (N)) mod the number of subframesexcluding subframes which can be MBSFN subframes=the subframes in oneradio frame for paging occasion (where they have the re-numberedsubframe numbers) (equation 2) can be considered.

In addition to the advantages provided by Embodiment 23, this variant 1can provide the following advantages. There can be provided an advantageof eliminating the necessity to store a large amount of information ofthe correspondence table in the network side and the mobile terminalside. There can be provided a further advantage of, even when thecorrespondence between the number of subframes excluding subframes whichcan be MBSFN subframes and the subframes in a radio frame for pagingoccasion is changed, informing only the expression showing the relationfrom the network side to the mobile terminal side, thereby eliminatingthe necessity to inform a large amount of information of thecorrespondence table.

Although the above-mentioned expression showing the relation can beapplied regardless of the method of determining a paging occasion (aradio frame for paging occasion), there occurs a case in which subframesto which paging occasions are actually allocated are arrangednon-uniformly in one radio frame. It can be considered that acomputation expression for determining a paging occasion is given by“paging occasion=(an identifier of each mobile terminal mod the numberof paging groups (N))×Int (the discontinuous reception cycle length inthe mixed frequency layer (T)/the number of paging groups (N))”. In thiscase, when equation 1 is applied to the determination of the subframesin one radio frame for paging occasion, the subframes to which pagingoccasions are allocated may be arranged non-uniformly. For example, in acase in which N=3 and the number of subframes excluding subframes whichcan be MBSFN subframes=3, the subframes to which paging occasions areallocated are arranged non-uniformly. Because N=3, a paging occasionoccurs in a radio frame of #0, though an identifier (IMSI or the like)of a mobile terminal allocated to this radio frame is an integralmultiple of 3. Therefore, when equation 1 is applied, the subframe inthis radio frame to which the paging occasion is allocated is the one of#0 for each of all mobile terminals. Thus, under certain circumstances,there can occur a case in which the subframes in one radio frame towhich paging occasions are actually allocated are arrangednon-uniformly. Hereafter, a method of preventing the subframes in oneradio frame to which paging occasions are actually allocated from beingarranged non-uniformly will be disclosed. For example, for thedetermination of both one radio frame for paging occasion, andsubframes, a method of performing a mod arithmetic operation on anidentifier of a mobile terminal with N and the number of subframesexcluding subframes which can be MBSFN subframes and a method of notperforming any mod arithmetic operation on an identifier of a mobileterminal are provided. As a concrete example, when (equation 1) is usedas the method of determining subframes, the following method ofdetermining a paging occasion, which is shown in Embodiment 2, isprovided.

“Paging Occasion=(IMSI div K) mod (the discontinuous reception cyclelength in a unicast/mixed frequency layer)+n×(the discontinuousreception cycle in the unicast/mixed frequency layer), where n: 0, 1, 2,or . . . , and Paging Occasion≦the maximum of SFN.

SFN is an integer ranging from 0 to the maximum of SFN. K is the numberof subframes excluding subframes which can be MBSFN subframes. When(equation 2) is used as the method of determining subframes, thefollowing method of determining a paging occasion is provided.Paging occasion=(an identifier of each mobile terminal mod the number ofpaging groups (N))×Int(the discontinuous reception cycle length (T) inthe mixed frequency layer/the number of paging groups (N))

When (equation 2) is used as the method of determining subframes, thefollowing method of determining a paging occasion is provided as ananother method.

“Paging occurrence radio frame” (Paging Occasion)=(IMSI or K) modX+n×(the discontinuous reception cycle length in an MBMS transmissionfrequency layer), where n: 0, 1, 2, or . . . , and Paging Occasion≦themaximum of SFN.

SFN is an integer ranging from 0 to the maximum of SFN. X is the numberof radio frames in each of which paging has occurred within adiscontinuous reception cycle in the MBMS transmission frequency layer,and satisfies the following inequality: X the discontinuous receptioncycle length (a number of radio frames) in the MBMS transmissionfrequency layer. The value of X (a remainder value at X) is associatedwith a radio frame number (SFN). By configuring the method in this way,there is provided an advantage of arbitrarily setting up a radio framein which paging occurs. When (equation 2) is used as the method ofdetermining subframes, the following method of determining a pagingoccasion is provided as an another method.

“Paging occurrence radio frame” (Paging Occasion)=((IMSI div K) mod(Int(T/TX)))×TX+n×(the discontinuous reception cycle length in the MBMStransmission frequency layer), where n: 0, 1, 2, or . . . , and PagingOccasion≦the maximum of SFN.

SFN is an integer ranging from 0 to the maximum of SFN. TX satisfies thefollowing inequality: TX≦the discontinuous reception cycle length (anumber of radio frames) in the MBMS transmission frequency layer.

Because it becomes unnecessary to associate the above-mentioned value ofX (the remainder value at X) with the radio frame number (SFN) by makinga radio frame in which paging occurs periodic, the equation fordetermining a paging occasion can be simplified.

The above-mentioned expression showing the relation can be determinedstatically. As a result, because the network side does not have toinform the correspondence table to the mobile terminal side, there canbe provided a further advantage of making effective use of the radioresources. On the other hand, if the expression showing the relation canbe changed, the expression showing the relation can be mapped onto abroadcast control channel (BCCH) as a logical channel, and the broadcastcontrol channel can be mapped onto a broadcast channel (BCH) which is atransport channel and the broadcast channel can be mapped onto aphysical broadcast channel (PBCH) which is a physical channel. Asanother concrete example, the expression showing the relation can bealternatively mapped onto the broadcast control channel (BCCH) as alogical channel, and this broadcast control channel can be mapped onto adownlink shared channel (DL-SCH) which is a transport channel and thedownlink shared channel can be mapped onto a physical downlink sharedchannel (PDSCH) which is a physical channel. By enabling thecorrespondence table to be changed, there can be provided a furtheradvantage of being able to construct the mobile communication systemwith flexibility. The concrete example of the above-mentioned expressionshowing the relation can provide the following advantage. Even if mobileterminals belong to the same paging group, the values of subframes inone radio frame for paging occasion change according to the identifiersof the mobile terminals. As a result, the number of mobile terminalsusing an identical subframe is reduced. Therefore, there can be providedan advantage of reducing the radio resources used for a PICH and a PCHin one subframe.

In this variant 2, a different method for use in the process of stepST4505 of Embodiment 23 will be shown. In this variant 2, therenumbering of subframes is not carried out. Each mobile terminaldetermines a subframe in a radio frame for paging occasion whilebringing it into correspondence with the information about MBSFNsubframe allocation received in step ST4502 (avoiding the allocation). Acorrespondence table is shown in FIG. 96 as a concrete example. FIG.96(a) will be explained. When the MBSFN subframe allocation shows “#1”,the determined subframe in one radio frame for paging occasion is “#4”.A correspondence table taking into consideration a case in which two ormore subframes occurs in one radio frame for paging occasion is shown inFIG. 96(b). For example, in a case in which the number of subframesoccurring in one radio frame for paging occasion shown in FIG. 96(b) is“2”, each mobile terminal cannot determine which one of the twosubframes, which is shown in the column corresponding to the case inwhich the number of subframes occurring in one radio frame for pagingoccasion shown in FIG. 96(b) is “2”, the mobile terminal itself shouldreceive (monitor) via discontinuous reception. This problem can besolved by using the following method. (The identifier of each mobileterminal mode the number of subframes for paging occasion in one radioframe) is determined. When the number of subframes for paging occasionin one radio frame is “2”, the solution of the above-mentioned equationis 0 or 1. Therefore, as a concrete example, when the solution of theabove-mentioned equation is “0”, the subframe number on the upper sideof each cell of the correspondence table is specified, whereas when thesolution of the above-mentioned equation is “1”, the subframe number onthe lower side of each cell of the correspondence table is specified. Asan alternative, the above-mentioned information can be included in thecorrespondence table. As another solution, each mobile terminal receives(monitors) all of the plurality of subframes for paging occasionexisting in one radio frame. As a result, the above-mentioned problem issolved. Furthermore, there can occur a case in which even though aplurality of paging occasions occur in one radio frame, a requirednumber of subframe numbers for paging occasion cannot be determinedbecause of a relation with the MBSFN subframe allocation. This problemcan be solved by using the following method. The number of paging groupsand/or the discontinuous reception cycle length (T) in the mixedfrequency layer and/or the MBSFN subframe allocation (the number ofallocations) is determined in such a way that the number of pagingoccasions existing in one radio frame is equal to or smaller than thenumber of subframes excluding subframes which can be MBSFN subframes. Inother words, the number (N) of paging groups, the discontinuousreception cycle length (T) in the mixed frequency layer, or the numberof MBSFN subframe allocations can be determined in such a way that thefollowing equation is satisfied:(“The number (N) of paging groups/the discontinuous reception cyclelength (T) in the mixed frequency layer=<10(the number of subframes inone radio frame−the number of MBSFN subframe allocations”)).

A concrete example of the above-mentioned case in which a plurality ofsubframes for paging occasion occur in one radio frame will be describedhereafter. A case in which nonpatent reference 5 is used in the methodof determining a radio frame for paging occasion will be considered. Aspreviously mentioned, it is described in nonpatent reference 5 that inorder to determine a paging occasion, two parameters including a paginginterval length (corresponding to the discontinuous reception cyclelength in the mixed frequency layer in the present invention) (T), andthe number (N) of paging occasions during a paging interval are needed,and no other parameters are needed. The case in which a plurality ofsubframes for paging occasion occur in one radio frame can be shown bythe following equation (1<N/T). A concrete example of the method ofusing FIG. 96(b) in this case will be shown hereafter. In the case of1<N/T=<2, two subframes corresponding to paging occasions of differentpaging groups exist in one radio frame. Therefore, in the case of1<N/T=<2, the column corresponding to the case in which the number ofsubframes for paging occasion occurring in one radio frame, shown inFIG. 96(b), is “2” is used.

The correspondence table as shown in FIG. 96 needs to be shared by thenetwork side and the mobile terminal side. As an alternative, thecorrespondence table can be determined statically in the mobilecommunication system. As a result, because the network side does nothave to inform the correspondence table to the mobile terminal side,there can be provided a further advantage of making effective use of theradio resources. On the other hand, if the correspondence table can bechanged, the correspondence table can be mapped onto a broadcast controlchannel (BCCH) as a logical channel, and the broadcast control channelcan be mapped onto a broadcast channel (BCH) which is a transportchannel and the broadcast channel can be mapped onto a physicalbroadcast channel (PBCH) which is a physical channel. As anotherconcrete example, the correspondence table can be alternatively mappedonto the broadcast control channel (BCCH) as a logical channel, and thisbroadcast control channel can be mapped onto a downlink shared channel(DL-SCH) which is a transport channel and the downlink shared channelcan be mapped onto a physical downlink shared channel (PDSCH) which is aphysical channel. By enabling the correspondence table to be changed,there can be provided a further advantage of being able to construct themobile communication system with flexibility.

In variant 2, a subframe in a radio frame for paging occasion is broughtinto correspondence with the information about MBSFN subframe allocationaccording to this MBSFN subframe allocation (in such a way that theallocation is avoided). Therefore, a subframe in a radio frame forpaging occasion and an MBSFN subframe are prevented from being anidentical subframe. Therefore, there can be provided an advantage ofbeing able to solve the problem of the present invention. Compared withEmbodiment 23 and variant 1, variant 2 can provide an advantage of beingable to eliminate the process of renumbering subframes in both themobile terminal side and the network side.

In this variant 3, a different method for use in the process of stepST4505 of Embodiment 23 will be shown. In this variant 3, it isconsidered that instead of the correspondence table, a relation betweenMBSFN subframe allocation and a subframe in a radio frame for pagingoccasion is maintained constant, unlike in variant 2. In other words, anexpression showing the relation between MBSFN subframe allocation and asubframe in a radio frame for paging occasion is defined. A concreteexample of the expression showing the relation will be shown hereafter.An explanation will be made with the subframe numbers of subframes whichare not renumbered. However, the concept of this variant can be usedeven in a case in which the renumbering of subframes is carried out.

The number of a subframe in a radio frame for paging occasion=the MBSFNsubframe allocation number+P (P: integer) When the number of a subframein a radio frame for paging occasion which is determined according tothe above-mentioned equation exceeds #9, the number of a subframe in aradio frame for paging occasion is given by

(The MBSFN subframe allocation number+P−(9×n)) (P: integer, n: positiveinteger, and n is incremented by “1” every time when the subframe numberexceeds 9).

It can also be expected that the subframe in a radio frame for pagingoccasion which is determined according to the above-mentioned equationcoincides with an MBSFN subframe. This problem can be solved as will beshown below.

The number of the subframe in a radio frame for paging occasion=theMBSFN subframe allocation number+P+(m×Q)−(9×n) (P: integer, n: positiveinteger, and m=1, 2, 3, . . . , or 10)

The value of m is incremented until the subframe in a radio frame forpaging occasion which is determined according to the above-mentionedequation has a value which does not coincide with that of an MBSFNsubframe.

Q is an integer which is 1 or an integer which has no factor in commonwith 10. Concretely, Q=1, 3, 7, 9, or . . . can be considered. At thistime, P can be set to be equal to Q.

The above-mentioned expression showing the relation can be determinedstatically. As a result, because the network side does not have toinform the correspondence table to the mobile terminal side, there canbe provided a further advantage of making effective use of the radioresources. On the other hand, if the expression showing the relation canbe changed, the expression showing the relation can be mapped onto abroadcast control channel (BCCH) as a logical channel, and the broadcastcontrol channel can be mapped onto a broadcast channel (BCH) which is atransport channel and the broadcast channel can be mapped onto aphysical broadcast channel (PBCH) which is a physical channel. Asanother concrete example, the expression showing the relation can bealternatively mapped onto the broadcast control channel (BCCH) as alogical channel, and this broadcast control channel can be mapped onto adownlink shared channel (DL-SCH) which is a transport channel and thedownlink shared channel can be mapped onto a physical downlink sharedchannel (PDSCH) which is a physical channel. By enabling thecorrespondence table to be changed, there can be provided a furtheradvantage of being able to construct the mobile communication systemwith flexibility.

In addition to the advantages provided by variant 2, this variant 3 canprovide the following advantages. There can be provided an advantage ofeliminating the necessity to store a large amount of information of thecorrespondence table in the network side and the mobile terminal side.There can be provided a further advantage of, even when thecorrespondence between MBSFN subframe allocation and a subframe in aradio frame for paging occasion is changed, informing only theexpression showing the relation from the network side to the mobileterminal side, thereby eliminating the necessity to inform a largeamount of information of the correspondence table.

In this variant 4, a different method for use in the process of stepST4505 of Embodiment 23 will be shown. A subframe excluding subframeswhich can be MBSFN subframes is defined as a subframe in a radio framefor paging occasion in the mobile communication system. More concretely,#0 and/or #5 onto which no MBSFN subframe is allocated is defined as asubframe in a radio frame for paging occasion because an SCH is mapped.A subframe in a radio frame for paging occasion can be determinedstatically. As a result, because the network side does not have toinform the subframe in a radio frame for paging occasion, there can beprovided a further advantage of making effective use of the radioresources. On the other hand, if the subframe in a radio frame forpaging occasion can be changed, the subframe in a radio frame for pagingoccasion can be mapped onto a broadcast control channel (BCCH) as alogical channel, and the broadcast control channel can be mapped onto abroadcast channel (BCH) which is a transport channel and the broadcastchannel can be mapped onto a physical broadcast channel (PBCH) which isa physical channel. As another concrete example, the subframe in a radioframe for paging occasion can be alternatively mapped onto the broadcastcontrol channel (BCCH) as a logical channel, and this broadcast controlchannel can be mapped onto a downlink shared channel (DL-SCH) which is atransport channel and the downlink shared channel can be mapped onto aphysical downlink shared channel (PDSCH) which is a physical channel. Byenabling the correspondence table to be changed, there can be provided afurther advantage of being able to construct the mobile communicationsystem with flexibility. In this variant 4, a subframe which avoids theMBSFN subframe allocation is defined as a subframe in a radio frame forpaging occasion. Therefore, the determined subframe in a radio frame forpaging occasion and an MBSFN subframe are prevented from being anidentical subframe. Therefore, there can be provided an advantage ofbeing able to solve the problem of the present invention. Compared withEmbodiment 23 and variant 1, variant 2 can provide an advantage of beingable to eliminate the process of renumbering subframes in both themobile terminal side and the network side. Compared with variant 2 andvariant 3, variant 4 can provide an advantage of being able to eliminatethe process of determining a subframe in a radio frame for pagingoccasion according to the MBSFN subframe allocation in both the mobileterminal side and the network side.

In this variant 5, a different method for use in the process of stepST4505 of Embodiment 23 will be shown. Each mobile terminal, in stepST4505, determines a subframe in a radio frame for paging occasion. Inthis variant 5, instead of step 4505, each mobile terminal carries out aprocess as shown in FIG. 97. Each mobile terminal, in step ST4901,determines a subframe in a radio frame for paging occasion. In variant5, a method of determining a subframe in a radio frame for pagingoccasion in step ST4901 is not specified particularly. A method whichdoes not take the MBSFN subframe allocation into consideration can beused. As a concrete example of the method of determining a subframe in aradio frame for paging occasion, the method described in Embodiment 2,or the method, as described in nonpatent reference 5, of using a fixedvalue regardless of the MBSFN subframe allocation can be used. Eachmobile terminal, in step ST4902, uses the MBSFN subframe allocationreceived in step ST4502 and the subframe in a radio frame for pagingoccasion determined in step ST4901 to determine whether or not both theMBSFN subframe and the subframe in a radio frame for paging occasion arean identical subframe. When they are an identical subframe, each mobileterminal makes a transition to step ST4903. In contrast, when they arenot an identical subframe, each mobile terminal ends the process withoutmaking a transition to step ST4903. More specifically, each mobileterminal uses the subframe in a radio frame for paging occasiondetermined in step ST4901 just as it is. Each mobile terminal, in stepST4903, changes the subframe in a radio frame for paging occasiondetermined in step ST4902 to a subframe other than the next subframewhich can be an MBSFN subframe. For example, a case in which thesubframe in a radio frame for paging occasion determined in step ST4901is #2, and the MBSFN subframe allocation received in step ST4502 shows#2 will be considered. In this case, it is determined in step ST4902that both of them are an identical subframe. Therefore, it is determinedin step ST4903 that the subframe in a radio frame for paging occasion isthe one other than the subframe which can be the next MBSFN subframe,i.e., #3. At this time, the subframe in a radio frame for pagingoccasion can be changed in step ST4903 to a subframe other than theprevious MBSFN subframe, i.e., #1. The determination of step ST4902 canbe carried out for each radio frame for paging occasion determined instep ST4503. Furthermore, the determination of step ST4902 can becarried out once when the serving cell in question starts discontinuousreception and/or once when the MBSFN subframe allocation is changed,i.e., a number of times corresponding to the repetition period of MBSFNframe clusters. In this case, if the subframe in a radio frame foreither one of paging occasions coincides with the MBSFN subframeallocation, the process of step ST4903 is performed on the subframe in aradio frame for each paging occasion. As an alternative, the process ofstep ST4903 can be performed on only the subframe in a radio frame forthe paging occasion in question (which coincides with the MBSFN subframeallocation). In this case, the process of step ST4903 is performed onthe subframe in a radio frame for the paging occasion in question (whichcoincides with the MBSFN subframe allocation) at the repetition periodsof MBSFN frame clusters. The serving cell, in step 4506, carries out thesame processes of step ST4901 to ST4903 as those performed by eachmobile terminal.

In addition, there can be a case in which the subframe in a radio framefor paging occasion which is determined through the process of stepST4903 is not placed in the same radio frame as that in which theoriginal subframe in a radio frame for paging occasion (the subframe ina radio frame for paging occasion which is determined in step ST4901) isto be placed. A process which is carried out in this case will bedescribed hereafter. The subframe in a radio frame for paging occasionwhich is determined through the process of step ST4903 can be placed ina radio frame different from that in which the original subframe in aradio frame for paging occasion is to be placed. As an alternative, thesubframe in a radio frame for paging occasion which is determined instep ST4901 can have a value which makes the subframe in a radio framefor paging occasion which is determined through the process of stepST4903 be placed in the same radio frame as that in which the originalsubframe in a radio frame for paging occasion is to be placed. As aconcrete example, a case in which the subframe in a radio frame forpaging occasion which is determined in step ST4901 is the last one (#9)of the subframes of the radio frame is excluded, or a case in which thesubframe in a radio frame for paging occasion which is determined instep ST4901 has a value ranging from a certain specified value to avalue corresponding to the last subframe is excluded. As a concreteexample of the subframe number having the certain specified value, “thesubframe number which is the certain specified value=the last subframenumber−the number of continuous allocations of MBSFN subframes” isprovided.

In this variant 5, after a subframe in a radio frame for paging occasionis determined without taking MBSFN subframes into consideration, if thesubframe in a radio frame for paging occasion coincides with an MBSFNsubframe, the subframe in a radio frame for paging occasion is changedto a subframe other than the subframe which can be the next MBSFNsubframe. Therefore, the determined subframe in a radio frame for pagingoccasion can be prevented from being the same subframe as an MBSFNsubframe. Therefore, there can be provided an advantage of being able tosolve the problem of the present invention.

In this variant 6, a different method for use in the process of stepST4503 of Embodiment 23 will be shown. A case of using the methoddescribed in nonpatent reference 5 in step ST4503 will be considered. Inthis case, a paging occasion is determined by assuming that a paginginterval length is equal to the number of paging occasions during thepaging interval. As a result, there can be provided an advantage ofreducing parameters for determining a paging occasion by one. Thisresults in reduction in the system information about the self-cell instep ST4001. As a result, there can be provided an advantage of makingeffective use of the radio resources.

Embodiment 23 and variants 1 to 6 can be applied to the “Unicast sidediscontinuous reception” shown in Embodiment 1 and Embodiment 2.

Embodiment 24

OFDM symbols other than the one or two leading OFDM symbols of eachMBSFN subframe are a resource dedicated to MBMS transmission. In a casein which a subframe in a radio frame for paging occasion coincides withMBSFN subframe allocation, any OFDM symbols other than the one or twoleading OFDM symbols of each MBSFN subframe are a resource dedicated toMBMS transmission and cannot be used for paging processing. Therefore,in order to solve a problem that inconvenience occurs in a conventionalpaging processing method, in this Embodiment 24, a processing method ofdealing with a case in which a subframe in a radio frame for pagingoccasion coincides with an MBSFN subframe will be disclosed. In thisEmbodiment 24, in the case in which a subframe in a radio frame forpaging occasion coincides with MBSFN subframe allocation, a radioresource other than the one or two leading OFDM symbols which is usedexclusively for MBSFN transmission is not used for unicast transmission,more concretely, for paging processing. Furthermore, in the case inwhich a subframe in a radio frame for paging occasion coincides withMBSFN subframe allocation, information regarding the paging processingwhich is transmitted with the radio resource other than the one or twoleading OFDM symbols which is used exclusively for MBSFN transmission istransmitted via a subframe other than the subframe which can be the nextMBSFN subframe. A concrete example of the processing method will beshown hereafter. A method of processing a paging signal is similar tothe process shown in FIG. 97 into which the process of step ST4505 ofFIG. 93 is changed. An explanation will be made focusing on a differentportion. Each mobile terminal, in step ST4902, uses MBSFN subframeallocation received in step ST4502 and a subframe in a radio frame forpaging occasion determined in step ST4901 to determine whether or notthey are an identical subframe. When they are an identical subframe,each mobile terminal makes a transition to step ST4903. In Embodiment24, instead of the process of step ST4903, each mobile terminal carriesout the following process. By using the one or two leading OFDM symbolsof the subframe in a radio frame for paging occasion determined in stepST4901, each mobile terminal transmits information which the mobileterminal has been scheduled to transmit via the one to three leadingOFDM symbols (an L1/L2 signaling channel) when the subframe in a radioframe for paging occasion does not coincide with MBSFN subframeallocation. Each mobile terminal also transmits information, which themobile terminal has been scheduled to transmit via OFDM symbols (aPDSCH) other than the one to three leading OFDM symbols when thesubframe in a radio frame for paging occasion does not coincide with theMBSFN subframe allocation, via OFDM symbols (a PDSCH) other than the oneto three leading OFDM symbols of a subframe other than the nextsubframes which can be MBSFN subframes. In this case in which theinformation is transmitted via OFDM symbols (a PDSCH) other than the oneto three leading OFDM symbols of a subframe other than the subframewhich can be the next MBSFN subframe, if allocation of a radio resourcein this PDSCH is the same as that when the subframe in a radio frame forpaging occasion does not coincide with the MBSFN subframe allocation,there can be provided an advantage of eliminating the necessity to carryout the allocation again and so on, thereby making effective use of theradio resources. When, in step ST4902, determining that the MBSFNsubframe and the subframe in a radio frame for paging occasion are notan identical subframe, each mobile terminal ends the processing withoutmaking a transition to step ST4903, that is, uses the subframe in aradio frame for paging occasion determined in step ST4901 just as it is.

A concrete example of the information which each mobile terminaltransmits by using the one or two leading OFDM symbols of the subframein a radio frame for paging occasion determined in step ST4901, andwhich the mobile terminal has been scheduled to transmit via the one tothree leading OFDM symbols (an L1/L2 signaling channel) when thesubframe in a radio frame for paging occasion does not coincide with theMBSFN subframe allocation will be shown hereafter. Nonpatent reference 1discloses that a PCH is mapped onto a PDSCH or a PDCCH. Nonpatentreference 1 also discloses that a paging group uses an L1/L2 signalingchannel (PDCCH) and that a precise identifier (UE-ID) of a mobileterminal can be found on a PCH. Therefore, a PCH is transmitted by usingan L1/L2 signaling channel. On the other hand, nonpatent reference 4describes that a PICH (Paging Indicator channel) for informingoccurrence of a paging signal destined for a mobile terminal belongingto a paging group is transmitted by using an L1/L2 signaling channel.

A concrete example of the information which each mobile terminal hasbeen scheduled to transmit via OFDM symbols (a PDSCH) other than the oneto three leading OFDM symbols when the subframe in a radio frame forpaging occasion does not coincide with the MBSFN subframe allocationwill be shown hereafter. Nonpatent reference 1 shows that whenallocation of a downlink radio resource for the next control informationis carried out via a PCH, this control information is mapped onto aPDSCH. On the other hand, nonpatent reference 4 describes that a PCH ismapped onto a PDSCH which is in the same subframe as that onto which aPICH is mapped.

In this Embodiment 24, in the case in which a subframe in a radio framefor paging occasion coincides with MBSFN subframe allocation, a radioresource other than the one or two leading OFDM symbols which is usedexclusively for MBSFN transmission is not used for unicast transmission,i.e., for the paging processing. Accordingly, even when a subframe in aradio frame for paging occasion coincides with MBSFN subframeallocation, there does not occur a case in which the network sidebecomes unable to transmit the information necessary for the pagingprocessing to each mobile terminal. Therefore, there can be provided anadvantage of being able to solve the problem of the present invention.

Variant 1 will be explained. In variant 1, when determining that theMBSFN subframe allocation received in step ST4502 and the subframe in aradio frame for paging occasion determined in step ST4901 are anidentical subframe, each mobile terminal carries out the followingprocesses instead of the processes of Embodiment 24. Each mobileterminal transmits both the information which the mobile terminal hasbeen scheduled to transmit via the one to three leading OFDM symbols (anL1/L2 signaling channel) when the subframe in a radio frame for pagingoccasion does not coincide with the MBSFN subframe allocation, and theinformation which the mobile terminal has been scheduled to transmit viaOFDM symbols (a PDSCH) other than the one to three leading OFDM symbolswhen the subframe in a radio frame for paging occasion does not coincidewith the MBSFN subframe allocation by using the one or two leading OFDMsymbols of the subframe in a radio frame for paging occasion determinedin step ST4901.

In this variant 1, in the case in which a subframe in a radio frame forpaging occasion coincides with MBSFN subframe allocation, a radioresource other than the one or two leading OFDM symbols which is usedexclusively for MBSFN transmission is not used for unicast transmission,i.e., for the paging processing. Accordingly, even when a subframe in aradio frame for paging occasion coincides with MBSFN subframeallocation, there does not occur a case in which the network sidebecomes unable to transmit the information necessary for the pagingprocessing to each mobile terminal. Therefore, there can be provided anadvantage of being able to solve the problem of the present invention.

Embodiment 25

In Embodiment 7, the configuration of carrying an indicator showingwhether or not a paging signal has been transmitted and the pagingsignal onto a PMCH of an MBSFN subframe is shown. On the other hand, inEmbodiment 8, the configuration of disposing a channel dedicated to apaging signal in an MBSFN subframe, and mapping all paging signals, suchas a paging message, paging message allocation information provided asinformation for informing the presence or absence of an incoming call,and 1-bit information showing the presence or absence of paging, onto achannel (DPCH) dedicated to a paging signal is disclosed. In thisembodiment, a method of mapping a paging signal onto both a PMCH and apaging signal dedicated channel in order to transmit the paging signalfrom an MBMS dedicated cell will be disclosed. Concretely, a PMCH and apaging signal dedicated channel are disposed in an identical MBSFNsubframe, and a part of a paging signal which is to be transmitted viaone subframe is mapped onto the PMCH, and the remaining paging signal ismapped onto the paging signal dedicated channel, so that the pagingsignal is transmitted.

An example of the configuration of disposing the paging signal dedicatedchannel and the PMCH in an identical MBSFN subframe is shown in FIG.100. The paging signal dedicated channel and the PMCH are disposed in anidentical MBSFN subframe. Information showing the presence or absence ofan incoming call in the above-mentioned MBSFN subframe is mapped ontothe paging signal dedicated channel (DPCH), and the remaining pagingsignal, e.g., paging message information is mapped onto the PMCH. As theinformation showing the presence or absence of an incoming call in theabove-mentioned MBSFN subframe, for example, information aboutallocation of a paging message is provided. As the information aboutallocation of a paging message, information about allocation of thepaging signal mapped onto the PMCH can be provided. As shown in thefigure, a PCFICH onto which information showing the number (k) of OFDMsymbols used for the DPCH is mapped can be provided. In this case, themethod disclosed in Embodiment 8 can be applied. The PCFICH does nothave to be provided. In this case, one of the methods, as disclosed inEmbodiment 8, of determining a physical area in an MBSFN subframe of aDPCH can be applied. For example, the method of making a physical areaonto which a paging signal is mapped specific to each MBSFN area, andderiving the physical area from an MBSFN-area-specific number (an MBSFNarea ID) or the like can be applied. By making a physical area ontowhich a paging signal is mapped be an identical physical area for eachMBSFN area, there can be provided an advantage of being able to transmitthe paging signal via a multi-cell transmission scheme. Accordingly,there can be provided an advantage of making it possible for each mobileterminal to carry out SFN combining of a paging signal, thereby reducingreceive errors occurring in the paging signal in each mobile terminal.This results in advantages, such as prevention of a control delay timein the whole mobile communication system, and effective use of the radioresources.

An example of a method of mapping paging information onto the physicalarea of each physical channel is shown in FIG. 101. As a method ofmapping the information about allocation of a paging message onto thepaging signal dedicated channel, the method disclosed in Embodiment 8can be applied. A base station maps the paging message allocationinformation for a mobile terminal for which an incoming call isoccurring onto the paging dedicated physical channel. The base stationmultiplies the paging message allocation information for each mobileterminal m for which an incoming call is occurring by an identificationnumber specific to this mobile terminal (process 1). Next, the basestation performs CRC (Cyclic Redundancy Check) addition on the result ofthis multiplication (process 2), and carries out a process includingencoding (Encode), rate matching, and interleaving (process 3). The basestation then allocates the result of the series of processes which ithas carried out to control information elements each having a sizecorresponding to the size of the physical area onto which the pagingmessage allocation information is to be mapped, and connects a pluralityof control information elements whose number is equal to that of themobile terminals for each of which an incoming call is occurring to oneanother (process 4). The base station performs a scrambling processusing an MBSFN-area-specific scrambling code (Scrambling Code), amodulation process, etc. on the connected result (process 5). Themodulation process can be specific to the MBSFN area. The result ofcarrying out these processes is mapped onto k leading OFDM symbols(process 6). At that time, the base station derives the number k ofrequired OFDM symbols on the basis of the result of the connection ofthe plurality of control information elements whose number is equal tothat of the mobile terminals for each of which an incoming call isoccurring, and performs a process including encoding on the indicatorcorresponding to the number k and then maps the indicator onto thePCFICH. These processes are carried out by using the same method in allthe cells in the MBSFN area, and multi-cell transmission of the pagingmessage allocation information is carried out in the MBSFN area. In thefigure, a case in which the number (k) of OFDM symbols via which theDPCH is transmitted is set to 1 is shown. The DPCH is mapped onto thefirst OFDM symbol of each subframe together with the PCFICH and areference symbol.

A mobile terminal which has received a signal which is transmittedthereto via the multi-cell transmission scheme determines the number ofOFDM symbols used for the paging on the basis of the result of decodingthe received PCFICH, and then carries out a demodulation process, adescrambling (Descrambling) process, and so on. After performing thoseprocesses, the mobile terminal divides the result of the processes intoparts each corresponding to a certain area, and successively performsdeinterleaving, decoding (Decoding), error detection, a correctionprocess, etc. on each of the parts to carry out blind detection with theterminal-specific identification number. After the mobile terminaldetects the identification number specific to the mobile terminal itselfthrough the blind detection, the mobile terminal can determine thatpaging is occurring, and can also receive the allocation informationabout the paging message destined for the mobile terminal itself. ThePCFICH, the reference symbol, and so on are mapped onto a physicalresource by using, for example, a predetermined method. As analternative, the same method as that used by a unicast cell can be used.By using the same method as that used by a unicast cell, it becomes ableto simplify the configuration of the base station and the configurationof the receiving circuit of each mobile terminal.

The base station also maps the paging message to a mobile terminal forwhich an incoming call is occurring onto the paging PMCH. The basestation multiplies the paging message to each mobile terminal m forwhich an incoming call is occurring by an identification code specificto the mobile terminal itself (a number or a sequence) (process 7),carries out CRC (Cyclic Redundancy Check) addition (process 8), and alsocarries out processes including encoding (Encode) and rate matching(process 9). The base station then performs a spreading process using anMBSFN-area-specific scrambling code (Scrambling code), a modulationprocess, etc. on the results of the series of processes carried out(process 10). The modulation process can be specific to the MBSFN area.The base station allocates the results of these processes carried out tothe physical area in the PMCH shown by the paging message allocationinformation mapped onto the paging dedicated channel (process 11).

As a method of enabling an MBMS dedicated cell to transmit a pagingsignal, the method disclosed in Embodiment 2 can be applied. A pagingsignal is transmitted together with an MCCH of a PMCH in Embodiment 2,whereas in this embodiment, a paging signal is transmitted via the PMCHprovided in an MBSFN subframe with which the information aboutallocation of a paging message is transmitted via the DPCH. As themethod of mapping a paging signal onto the PMCH, Embodiment 7 can beapplied. In the case of this embodiment, because each mobile terminaldoes not have to receive a paging signal when receiving an MCCH, unlikein the case of Embodiment 2, there is no necessity to impose alimitation of making the MBSFN subframes onto which an MCCH and a PCCHare mapped respectively adjacent in time to each other. In accordancewith this embodiment, each mobile terminal receives an MBSFN subframeonto which the paging signal is mapped separately from an MCCH. To thisend, for example, when performing an operation of making preparationsfor discontinuous reception at the time of MBMS reception in ST1735,each mobile terminal determines, instead of a paging group, an MBSFNframe and an MBSFN subframe onto which the paging message allocationinformation is mapped. These MBSFN frame and MBSFN subframe can bedetermined on the basis of a mobile-terminal-specific identificationnumber (UE-ID or the like), a discontinuous reception cycle length, andDRX information according to a computation expression. What is necessaryis just to enable the network side, the base station and each mobileterminal to determine them by using the same parameters and the samecomputation expression. This computation expression can bepredetermined. As a method of deriving the above-mentioned MBSFN frameand MBSFN subframe in which the paging signal occurs, the method inaccordance with Embodiment 15 can also be applied. When paging occurs,an MCE which, in ST1777, receives a paging request from an MME, ST1778,determines an MBSFN frame and an MBSFN subframe onto which pagingmessage allocation information is mapped, like in ST1735. The MCE, inST1779, determines an area to which a paging message on a PMCH isallocated, as well as the scheduling of the paging signal. With thepaging request signal of ST1780, the MCE transmits information about thescheduling of this paging signal and the paging message allocationinformation on the PMCH to an MBMS dedicated cell. In the MBSFN frameand the MBSFN subframe which are derived in the above-mentioned step,just like in ST1735, the MBMS dedicated cell, in ST1782, maps the pagingmessage allocation information onto the DPCH and also maps the pagingmessage onto the PMCH of the same subframe on the basis the informationtransmitted with the paging request which it has received, and thentransmits them to mobile terminals being served thereby. On the otherhand, each mobile terminal determines whether or not they are the MBSFNframe and the MBSFN subframe which the mobile terminal, in ST1735, hasderived separately from the MCCH. This operation is added after ST1772.When it is not the MBSFN subframe onto which the paging signal ismapped, each mobile terminal makes a transition to ST1788. In contrast,when it is the MBSFN subframe onto which the paging signal is mapped,each mobile terminal, in ST1784, receives not the PMCH but the DPCH, andcarries out blind detection of the information mapped onto the DPCH withthe identification number specific to the mobile terminal itself, asmentioned above. When, in ST1785, detecting that the information is thepaging message allocation information destined for the mobile terminalitself through the blind detection, each mobile terminal, in ST1786,receives the paging information on the PMCH according to this pagingmessage allocation information. Each mobile terminal, in ST1787, becomesable to receive the paging message destined for the mobile terminalitself certainly by detecting the paging information on the PMCH withthe identification number specific to the mobile terminal itself. When,in ST1785, detecting that the information is not the paging messageallocation information destined for the mobile terminal itself throughthe blind detection, each mobile terminal makes a transition to ST1788.

In the above-mentioned example, the process of multiplying the pagingsignal destined for each of the mobile terminals by the identificationcode specific to the mobile terminal itself in the processes 1 and 7disclosed with reference to FIG. 101 is carried out. The base stationcan alternatively use another processing method of adding the pagingsignal destined for each of the mobile terminals and an identificationnumber specific to this mobile terminal, as shown in Embodiment 2,Embodiment 7, Embodiment 8, and so on. In this case, each of the mobileterminals receives either a physical area (in this case, an areaexcluding the DPFICH and RS in the 1st OFDM symbol) used for the pagingsignal on the DPCH (in this case, the paging message allocationinformation) or a physical area (in this case, an area shown by thepaging message allocation information) used for the paging signal on thePMCH (in this case, the paging message), carries out demodulation anddescrambling using an MBSFN-area-specific scrambling code, and dividesthe result of the demodulation and descrambling into parts eachcorresponding to an information element unit, and performs a processincluding decoding on each of the divided parts each corresponding to aninformation element unit. Each of the mobile terminals then determineswhether the mobile-terminal-specific identification number exists in theinformation on which the mobile terminal itself has performed theprocess including decoding to detect the paging signal destinedtherefor. Each of the mobile terminals does not have to perform the sameprocess on each physical channel, and can alternatively set up either aprocess of carrying out a multiplication by an identification codespecific to the mobile terminal itself, and a process of carrying out anaddition of an identification number specific to the mobile terminalitself for each physical channel.

Furthermore, as shown in Embodiment 2 and Embodiment 7, in order todistinguish the physical channel onto which a paging signal is mappedfrom any other information, this information can be multiplied by anidentifier (ID) specific to the type of the information. Because anidentifier specific to each information type is used for MBSFN subframeswhich are transmitted via a multi-cell transmission scheme, unlike inthe case of unicast communications, an identical identifier specific toa specific type of information needs to be transmitted from a pluralityof cells which carry out multi-cell transmission. For example, anidentifier specific to each identical information type is used in eachMBSFN area. As an example, an MBMS dedicated cell multiplies a pagingsignal by an identifier for the paging signal and transmits the pagingsignal. A mobile terminal which needs to receive the paging signal,among mobile terminals being served by the MBMS dedicated cell, carriesout blind detection of the paging signal by using the identifier for thepaging signal. As a result, there can be provided an advantage ofenabling such a mobile terminal to receive required information when themobile terminal requires the information. Accordingly, there can beprovided an advantage of reducing the power consumption of the mobileterminal. There can be provided a further advantage of preventing acontrol delay time from occurring in the mobile terminal. The identifierdifferent for each information type can be predetermined, or can bebroadcast via broadcast information from a serving cell. As analternative, the identifier different for each information type can bebroadcast from the MBMS dedicated cell. Furthermore, because bymultiplying or adding the paging signal by or to themobile-terminal-specific identifier, each of the mobile terminalsbecomes able to carry out blind detection, it becomes unnecessary to fixthe physical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, the mapping can becarried out with flexibility, and there is provided an advantage ofimproving the use efficiency of the physical resources.

By configuring the method in this way, it becomes able to transmit apaging signal to each mobile terminal from an MBMS dedicated cell byusing the method disclosed in this embodiment. In addition, by using themethod disclosed in this embodiment, the necessity to map all pagingsignals onto one physical channel can be eliminated. Therefore, there isprovided an advantage of being able to carry out the scheduling oftransmission of the DPCH and the PMCH with flexibility, and to improvethe use efficiency of the radio resources. Furthermore, the pagingmessage mapped onto the PMCH can be mapped to a physical area in thePMCH with flexibility by mapping the information about allocation of thepaging message onto the DPCH. As a result, the use efficiency of theradio resources can be improved.

In this embodiment, Embodiment 8 and Embodiment 15, the dedicatedchannel onto which a paging signal is mapped is the DPCH, as mentionedabove. In a case in which a physical channel via which multi-celltransmission can be carried out, as well as a PMCH, exist in an MBSFNsubframe, a paging signal can be alternatively mapped onto this physicalchannel. Because a paging signal has only to be transmitted via an MBSFNsubframe and therefore it is not necessary to provide a new DPCH, thereis provided an advantage of simplifying the control operation, reducingthe circuit scale, and reducing the power consumption. As analternative, a physical channel for control information transmissionwhich can be transmitted via a multi-cell transmission scheme can beprovided in an MBSFN subframe. Also in this case, because it is notnecessary to provide a physical channel dedicated to paging, andtherefore a paging signal can be transmitted together with other controlinformation by using the above-mentioned physical channel, there isprovided an advantage of simplifying the control operation, reducing thecircuit scale, and reducing the power consumption. For example, theother control information can be system information.

When a paging signal is transmitted together with the other controlinformation by using the above-mentioned physical channel, it isnecessary to distinguish the paging signal from the other information.Therefore, the information mapped onto this physical channel can bemultiplied by an identifier (ID) specific to each information type. Asan alternative, only a specific type of information can be multiplied byan identifier specific to the specific type of information. Because anidentifier specific to each information type is used for MBSFN subframeswhich are transmitted via the multi-cell transmission scheme, unlike inthe case of unicast communications, an identical identifier specific toa specific type of information needs to be transmitted from a pluralityof cells which carry out multi-cell transmission. For example, anidentifier specific to each identical information type is used in eachMBSFN area. Thus, multi-cell transmission can be supported. As aconcrete example of carrying out a multiplication by an identifierspecific to each information type, a case in which a paging signal(e.g., paging message allocation information) and system information aretransmitted via the above-mentioned physical channel will be considered.The paging message allocation information is multiplied by an identifierfor the paging signal and the system information is multiplied by anidentifier for the system information, and they are transmitted by usingthe above-mentioned physical channel. A mobile terminal which needs toreceive the paging signal, among the mobile terminals being served bythe MBMS dedicated cell in question, carries out blind detection of thepaging message allocation information by using the identifier for thepaging signal. When the paging message allocation information exists,the mobile terminal receives the paging signal (paging message) in thephysical area in the PMCH constructed of, for example, the same frame,the physical area being shown by the paging message allocationinformation. The mobile terminal which has received the paging signal(paging message) of the physical area shown by the paging messageallocation information carries out processes including demodulation anddecoding, and determines whether this paging message is destined for themobile terminal itself by determining whether the identification numberspecific to the mobile terminal itself exists in the decodedinformation. By carrying out the determination in this way, the mobileterminal which needs to receive the paging signal can detect and receiveonly the paging signal. As a result, there can be provided an advantageof enabling such a mobile terminal to receive required information whenthe mobile terminal requires the information. Accordingly, there can beprovided an advantage of reducing the power consumption of the mobileterminal. There can be provided a further advantage of preventing acontrol delay time from occurring in the mobile terminal. The identifierspecific to each information type can be predetermined, or can bebroadcast via broadcast information from a serving cell. As analternative, the identifier specific to each information type can bebroadcast from the MBMS dedicated cell. Furthermore, because bymultiplying or adding the paging signal by or to themobile-terminal-specific identifier, each of the mobile terminalsbecomes able to carry out blind detection, it becomes unnecessary to fixthe physical area onto which the paging signal destined for each of themobile terminals is mapped in advance. Therefore, the mapping can becarried out with flexibility, and there is provided an advantage ofimproving the use efficiency of the physical resources.

Embodiment 26

In this embodiment, another concrete example of the “MBMS search”operation described in Embodiment 1, Embodiment 2, and so on will bedisclosed. An MBSFN area number (ID) informed from a cell in a unicastcell or an MBMS/unicast-mixed cell described in Embodiment 18 andEmbodiment 19 to mobile terminals being served by the cell is used forthe “MBMS search”. The MBSFN area number (ID) informed from a cell in aunicast cell or an MBMS/unicast-mixed cell to mobile terminals beingserved by the cell is used for establishment of synchronization in afrequency layer dedicated to MBMS. The MBSFN area number (ID) informedfrom a cell in a unicast cell or an MBMS/unicast-mixed cell to mobileterminals being served by the cell is used for establishment of framesynchronization in the frequency layer dedicated to MBMS.

An MBSFN area number (ID) informed from a serving cell which is aunicast cell or an MBMS/unicast-mixed cell described in Embodiment 18and Embodiment 19 to mobile terminals being served by the serving cellis used for the “MBMS search”. The MBSFN area number (ID) informed froma serving cell which is a unicast cell or an MBMS/unicast-mixed cell tomobile terminals being served by the serving cell is used forestablishment of synchronization in a frequency layer dedicated to MBMS.The MBSFN area number (ID) informed from a serving cell which is aunicast cell or an MBMS/unicast-mixed cell to mobile terminals beingserved by the serving cell is used for establishment of framesynchronization in the frequency layer dedicated to MBMS. A concreteexample of a method of informing an MBSFN area ID from a unicast cell,an MBMS/unicast-mixed cell, or a serving cell which is a unicast cell oran MBMS/unicast-mixed cell will be disclosed hereafter. A unicast cellor an MBMS/unicast-mixed cell maps an MBSFN area ID onto a broadcastcontrol channel (BCCH) which is a logical channel, and maps thebroadcast control channel onto a broadcast channel (BCH) which is atransport channel and further maps the broadcast channel onto a physicalbroadcast channel (PBCH) which is a physical channel to inform the MBSFNarea ID to mobile terminals being served thereby. As an alternative, theunicast cell or the MBMS/unicast-mixed cell maps the MBSFN area ID ontomaster information and further maps the master information onto thebroadcast control channel (BCCH) which is a logical channel, and mapsthe broadcast control channel onto the broadcast channel (BCH) which isa transport channel and further maps the broadcast channel onto thephysical broadcast channel (PBCH) which is a physical channel to informthe MBSFN area ID to the mobile terminals being served thereby.

As another informing method, the unicast cell or the MBMS/unicast-mixedcell maps the MBSFN area ID onto the broadcast control channel (BCCH)which is a logical channel, and maps the broadcast control channel ontoa downlink shared channel (DL-SCH) which is a transport channel andfurther maps the downlink shared channel onto a physical downlink sharedchannel (PDSCH) which is a physical channel to inform the MBSFN area IDto the mobile terminals being served thereby. As an alternative, theunicast cell or the MBMS/unicast-mixed cell maps the MBSFN area ID ontosystem information and further maps the system information onto thebroadcast control channel (BCCH) which is a logical channel, and mapsthe broadcast control channel onto the downlink shared channel (DL-SCH)which is a transport channel and further maps the downlink sharedchannel onto the physical downlink shared channel (PDSCH) which is aphysical channel to inform the MBSFN area ID to the mobile terminalsbeing served thereby. As another informing method, the unicast cell orthe MBMS/unicast-mixed cell maps the MBSFN area ID onto either a commoncontrol channel (CCCH) which is a logical channel or a dedicated controlchannel (DCCH), and maps the common control channel or dedicated controlchannel onto the downlink shared channel (DL-SCH) which is a transportchannel and further maps the downlink shared channel onto the physicaldownlink shared channel (PDSCH) which is a physical channel to informthe MBSFN area ID to the mobile terminals being served thereby.

A concrete example of how to inform an MBSFN area ID will be disclosed.A frequency of an available MBMS service, i.e., a frequency of areceivable MBSFN synchronization area (referred to as f(MBMS)), and anMBSFN area ID are informed. The MBSFN area ID and f(MBMS) can beinformed simultaneously or unsimultaneously. As an alternative, insteadof broadcasting all MBSFN area IDs included in f(MBMS), only an MBSFNarea ID which each mobile terminal being served by the unicast cell inquestion or the MBMS/unicast-mixed cell in question can receive actuallycan be broadcast. In other words, only the ID of an MBSFN area whichoverlaps the unicast cell in question or the MBMS/unicast-mixed cell inquestion geographically can be broadcast. As a result, only the MBSFNarea ID which each mobile terminal can receive can be used for the MBMSsearch, and therefore there can be provided an advantage of preventing acontrol delay time from occurring. As an alternative, f(MBMS) and MBSFNarea IDs included in the MBSFN synchronization area can be informed. TheMBSFN area IDs and f(MBMS) can be informed simultaneously orunsimultaneously. As an alternative, instead of broadcasting all MBSFNarea IDs included the MBSFN synchronization area, only an MBSFN area IDwhich each mobile terminal being served by the unicast cell in questionor the MBMS/unicast-mixed cell in question can receive actually can bebroadcast. In other words, only the ID of an MBSFN area which overlapsthe unicast cell in question or the MBMS/unicast-mixed cell in questiongeographically can be broadcast. As a result, only the MBSFN area IDwhich each mobile terminal can receive can be used for the MBMS search,and therefore there can be provided an advantage of preventing a controldelay time from occurring. In the above-mentioned concrete example, theMBSFN area IDs can be informed as the MBSFN synchronization areaidentifier (ID). As an alternative, a part of cell IDs used in theunicast/mixed frequency layer can be used as the MBSFN area IDs. A partof physical layer cell identities (Physical Layer cell identities) usedin the unicast/mixed frequency layer can be alternatively used as theMBSFN area IDs. f(MBMS) and a region of cell IDs or physical layeridentities which can be used for the MBSFN area IDs are informed.f(MBMS) and the above-mentioned region can be informed simultaneously orunsimultaneously.

As an alternative, the above-mentioned region of cell IDs or physicallayer identities which can be used for the MBSFN area IDs can bepredetermined statically (Static). Because it becomes unnecessary toinform the parameter from the network side to each mobile terminal byusing the radio resources, there can be provided an advantage of makingeffective use of the radio resources, and so on. Furthermore, because noradio resource is used for the transmission, there can also be providedan advantage of preventing receiving errors from occurring. A concreteexample of the MBMS search operation will be disclosed hereafter. Thisexample will be explained with reference to FIGS. 17 and 18 shown inEmbodiment 2. The unicast cell or the MBMS/unicast-mixed cell, in stepST1707, broadcasts one or more frequencies f(MBMS) to mobile terminalsby using a BCCH. The cell broadcasts one or more MBSFN area IDs includedin the one or more frequencies f(MBMS) together with the one or morefrequencies f(MBMS). The one or more frequencies f(MBMS) and the one ormore MBSFN area IDs can be informed simultaneously or unsimultaneously.Each of the mobile terminals, in step ST1708, receives the one or morefrequencies f(MBMS) and the one or more MBSFN area IDs included in theone or more frequencies f(MBMS) which are transmitted thereto by usingthe BCCH from the serving base station. An MBMS dedicated cell, in stepST1723, broadcasts a primary synchronization channel (P-SCH), asecondary synchronization channel (S-SCH), a reference signal (RS(MBMS)), a BCCH to mobile terminals being served thereby. Although theP-SCH can be an added sequence for exclusive use in a frequency layerdedicated to MBMS transmission, which has been debated in the 3GPP, thesame P-SCH as that for use in a unicast/mixed frequency layer is used inthis concrete example.

The S-SCH is brought into correspondence with an MBSFN area ID. TheS-SCH can be uniquely brought into correspondence with an MBSFN area ID.As an alternative, an MBSFN area ID can be identified from a sequence inwhich the P-SCH and the S-SCH are united. Each of the mobile terminals,in step ST1724, receives the P-SCH, the S-SCH, the RS (MBMS), and theBCCH (a broadcast control channel) from the MBMS dedicated cell. Each ofthe mobile terminals, in step ST1725, performs a searching operation ofsearching for an MBMS. Each of the mobile terminals carries out thesearch operation of searching for an MBMS on the basis of the one ormore frequencies f(MBMS) and the one or more MBSFN area IDs included inf(MBMS) which are received from the serving base station. Each of themobile terminals carries out the search operation of searching for anMBMS on the basis of the MBSFN area ID included in f(MBMS) to which themobile terminal has switched in step ST1722. Each of the mobileterminals carries out blind detection by using the same P-SCH as that inthe unicast/mixed frequency layer instead of the added sequence forexclusive use in the frequency layer dedicated to MBMS transmissionwhich has been debated in the 3GPP. Each of the mobile terminals whichhas blind-detected the P-SCH can carry out 5 ms-timing detection. Next,each of the mobile terminals carries out blind detection of the S-SCH byusing the one or more MBSFN area IDs received in step ST1708.

Each of the mobile terminals which has blind-detected the S-SCH cancarry out 10 ms-timing detection. A comparison with the method of addinga sequence for exclusive use in the frequency layer dedicated to MBMStransmission to the P-SCH, which has been debated in the 3GPP, will bemade. In accordance with the conventional technology, the number oftimes that the blind detection of the S-SCH is carried out correspondsto all sequences allocated for MBSFN area IDs. In contrast with this, inaccordance with this embodiment, the number of times that the blinddetection of the S-SCH is carried out can be made to be equal to thenumber of MBSFN area IDs received in step ST1708, and therefore can bereduced greatly. For example, in this embodiment, when the number ofMBSFN area IDs received in step ST1708 is one, the blind detection ofthe S-SCH has only to be carried out only once. As a result, there canbe provided an advantage of preventing a control delay time fromoccurring in the mobile communication system. Furthermore, there can beprovided an advantage of establishing low power consumption in eachmobile terminal. Each of the mobile terminals receives the BCCH by usinga scrambling code (Scrambling Code) related to the MBSFN area ID.Because the subsequent processes are the same as those of a concreteexample shown in Embodiment 2 and so on, the explanation of theprocesses will be omitted hereafter.

Next, variant 1 of this Embodiment will be explained. Another concreteexample of the search operation will be disclosed hereafter. Each of themobile terminals acquires prescribed information from an MBSFN area ID,and searches for an MBMS on the basis of the prescribed information (ora specific symbol or sequence). Because the same methods as thosementioned above can be used as a concrete example of the method ofinforming an MBSFN area ID from a unicast cell, an MBMS/unicast-mixedcell, or a serving cell which is a unicast cell or an MBMS/unicast-mixedcell and a concrete example of how to inform the MBSFN area ID, theexplanation of the methods will be omitted. Each of the mobile terminalsdetermines the prescribed information (or the specific symbol orsequence) from the MBSFN area ID. An identical computation expression isused by the network side and the mobile terminal side. As a result, thetransmission of the small amount of information which is the MBSFN areaID from the network side to each of the mobile terminals makes itpossible for the network side and each of the mobile terminals toacquire the prescribed information common to them. There can be providedan advantage of making effective use of the radio resources. Acorrespondence between the MBSFN area ID and the prescribed information(or the specific symbol or sequence) can be predetermined statically(Static). Because the transmission of the information from the networkside to each mobile terminal can be therefore eliminated, there can beprovided an advantage of making effective use of the radio resources.Furthermore, because no radio resource is used for the transmission,there can also be provided an advantage of preventing receiving errorsfrom occurring. Because each of the mobile terminals does not have todetermine the prescribed information, there can be provided an advantageof preventing a control delay time from occurring in each of the mobileterminals.

The prescribed information (or the specific symbol or sequence) which isbrought into correspondence with the MBSFN area ID can be alternativelytransmitted from the serving cell to the mobile terminals being servedby the serving cell. Because each of the mobile terminals does not haveto determine the prescribed information, there can be provided anadvantage of preventing a control delay time from occurring in each ofthe mobile terminals. A concrete example of how to use the prescribedinformation will be disclosed hereafter. The MBMS dedicated cell insertsthe prescribed information physically, and each of the mobile terminalscarries out blind detection by using prescribed information. A concreteexample of a method of mapping the prescribed information will bedisclosed. The prescribed information is mapped onto a physical channeltransmitted via a multi-cell transmission scheme. The prescribedinformation is mapped as a specific length. The prescribed informationis mapped at fixed periods. As a concrete example, the prescribedinformation is mapped onto each radio frame. Accordingly, each of themobile terminals can establish frame synchronization. The prescribedinformation can be mapped onto each subframe. Accordingly, each of themobile terminals can establish subframe synchronization. The prescribedinformation can be mapped onto a predetermined frequency. As a concreteexample, the prescribed information is mapped onto a number ofsubcarriers at the center of the system bandwidth. By mapping theprescribed information onto a number of subcarriers at the center of thesystem bandwidth, there can be provided an advantage of eliminating thenecessity for each mobile terminal to know the bandwidth at the time ofperforming the search operation of searching for an MBMS. A concreteexample of the search operation of searching for an MBMS will bedisclosed.

The search operation will be explained with reference to FIGS. 17 and 18of Embodiment 2. The unicast cell or the MBMS/unicast-mixed cell, instep ST1707, broadcasts one or more frequencies f(MBMS) to mobileterminals by using the BCCH. The cell broadcasts one or more MBSFN areaIDs included in the one or more frequencies f(MBMS) together with theone or more frequencies f(MBMS). The one or more frequencies f(MBMS) andthe one or more MBSFN area IDs can be informed simultaneously orunsimultaneously. Each of the mobile terminals, in step ST1708, receivesthe one or more frequencies f(MBMS) and the one or more MBSFN area IDsincluded in the one or more frequencies f(MBMS) which are transmittedthereto by using the BCCH from the serving base station. An MBMSdedicated cell, in step ST1723, determines prescribed information on thebasis of the ID of the MBSFN area to which the self-cell belongs. TheMBMS dedicated cell broadcasts the prescribed information, a referencesignal (RS(MBMS)), and a BCCH to mobile terminals being served thereby.As a concrete example of a method of transmitting the prescribedinformation, the above-mentioned method can be used. In this case, as aconcrete example, the prescribed information is broadcast with a numberof subcarriers at the center of the system bandwidth every radio frame.The number of subcarriers can be determined statically (Static), or canbe informed from the network side. In a case in which the MBMS dedicatedcell belongs to a plurality of MBSFN areas, the MBMS dedicated cell cantransmit the pieces of prescribed information corresponding to the MBSFNareas which the MBMS dedicated cell belongs in order. As a concreteexample, the MBMS dedicated cell can transmit the plural pieces ofprescribed information corresponding to the plurality of MBSFN areas byusing TDM or CDM.

Each of the mobile terminals, in step ST1724, receives the prescribedinformation, the RS(MBMS) and the BCCH (broadcast control channel) fromthe MBMS dedicated cell. Each of the mobile terminals, in step ST1725,carries out the search operation of searching for an MBMS. Each of themobile terminals carries out the search operation of searching for anMBMS on the basis of the one or more frequencies f(MBMS) and the one ormore MBSFN area IDs included in f(MBMS) which are received from theserving base station. Each of the mobile terminals carries out thesearch operation of searching for an MBMS on the basis of the MBSFN areaID included in f(MBMS) to which the mobile terminal has switched in stepST1722. Each of the mobile terminals determines prescribed informationon the basis of the MBSFN area ID. Each of the mobile terminals carriesout blind detection with the prescribed information. Each of the mobileterminals carries out blind detection with a number of subcarriers atthe center of the system bandwidth. Accordingly, each of the mobileterminals can establish radio frame synchronization. Each of the mobileterminals receives the BCCH by using a scrambling code (Scrambling Code)related to the MBSFN area ID. Because the subsequent processes are thesame as those of a concrete example shown in Embodiment 2 and so on, theexplanation of the processes will be omitted hereafter. This method caneliminate the transmission of the P-SCH and the S-SCH from the MBMSdedicated cell. As a result, there can be provided an advantage ofmaking effective use of the radio resources.

Next, variant 2 of this embodiment will be explained. Another concreteexample of the search operation will be disclosed hereafter. Each of themobile terminals acquires prescribed information from an MBSFN area ID,and searches for an MBMS on the basis of the prescribed information (ora specific symbol or a sequence). Because the same methods as thosementioned above can be used as a concrete example of the method ofinforming an MBSFN area ID from a unicast cell, an MBMS/unicast-mixedcell, or a serving cell which is a unicast cell or an MBMS/unicast-mixedcell, a concrete example of how to inform the MBSFN area ID, and themethod of acquiring the prescribed information, the explanation of themethods will be omitted. A concrete example of how to use the prescribedinformation will be disclosed hereafter. The MBMS dedicated cellmultiplies certain information by the prescribed information, and eachof the mobile terminals carries out blind detection by using theprescribed information. The MBMS dedicated cell performs scrambling oncertain information by using the prescribed information, and each of themobile terminals carries out blind detection by using the prescribedinformation. As a concrete example of the certain information, theP-SCH, the S-SCH, or the like can be provided. The MBMS dedicated cellcan perform the scrambling on the certain information at fixed periods.As a concrete example of the length of each of the fixed periods, anumber of radio frames or subframes or the like can be provided. TheMBMS dedicated cell can alternatively perform spreading on certaininformation by using the prescribed information, and each of the mobileterminals can carry out blind detection by using the prescribedinformation. As a concrete example of the certain information, theP-SCH, the S-SCH, or the like can be provided. The MBMS dedicated cellcan perform the spreading on the certain information at fixed periods.As a concrete example of the length of each of the fixed periods, anumber of radio frames or subframes or the like can be provided. Thismethod can eliminate the transmission of the P-SCH and the S-SCH fromthe MBMS dedicated cell. As a result, there can be provided an advantageof making effective use of the radio resources.

Embodiment 27

In each of a unicast cell and an MBMS/unicast-mixed cell, systeminformation is mapped onto a broadcast control channel (BCCH) which is alogical channel, and the broadcast control channel is mapped onto adownlink shared channel (DL-SCH) which is a transport channel and thedownlink shared channel is further mapped onto a physical downlinkshared channel (PDSCH) which is a physical channel, so that the systeminformation is informed to mobile terminals. In contrast, it is unknownwhether a PDSCH exists in a physical channel of an MBMS dedicated cell.A problem is therefore that any method of transmitting systeminformation from an MBMS dedicated cell to mobile terminals being servedby the MBMS dedicated cell is not established. In each of a unicast celland an MBMS/unicast-mixed cell, the system information is specific tothe cell. In contrast, an MBMS dedicated cell needs multi-celltransmission in an MBSFN area. Therefore, it is impossible to apply amethod of transmitting the system information in each of a unicast celland an MBMS/unicast-mixed cell, the system information being specific tothe cell, to an MBMS dedicated cell which needs multi-cell transmission,just as it is. A solution of the above-mentioned problem will bedisclosed hereafter. An MBMS dedicated cell maps the system informationonto a PMCH to transmit the system information to mobile terminals beingserved thereby. At that time, the MBMS dedicated cell can map the systeminformation as an information element of an MCCH or an MTCH, or can mapthe system information physically. In the case of mapping the systeminformation physically, the MBMS dedicated cell needs to map the systeminformation onto a physical resource in the PMCH which is identified incommon by the network side and the UE side. A method of informing aparameter regarding the physical resource which is identified in commonby the network side and the UE side will be disclosed hereafter.

The MBMS dedicated cell broadcasts the parameter regarding the physicalresource which is identified in common. The parameter regarding thephysical resource which is identified in common is mapped onto abroadcast control channel (BCCH) which is a logical channel, and thebroadcast control channel is mapped onto a broadcast channel (BCH) whichis a transport channel and the broadcast channel is further mapped ontoa physical broadcast channel (PBCH) which is a physical channel toinform the parameter to mobile terminals. As an alternative, theparameter regarding the physical resource which is identified in commoncan be mapped onto master information and the master information can bemapped onto a master information block (MIB), the master informationblock can be mapped onto the broadcast control channel (BCCH) which is alogical channel, and the broadcast control channel can be mapped ontothe broadcast channel (BCH) which is a transport channel and thebroadcast channel can be further mapped onto the physical broadcastchannel (PBCH) which is a physical channel to inform the parameter tothe mobile terminals.

As another informing method, the unicast cell or the MBMS/unicast-mixedcell broadcasts or informs the parameter regarding the physical resourcewhich is identified in common. The parameter regarding the physicalresource which is identified in common is mapped onto a broadcastcontrol channel (BCCH) which is a logical channel, and the broadcastcontrol channel is mapped onto a broadcast channel (BCH) which is atransport channel and the broadcast channel is further mapped onto aphysical broadcast channel (PBCH) which is a physical channel to informthe parameter to mobile terminals. As an alternative, the parameterregarding the physical resource which is identified in common can bemapped onto master information and the master information can be mappedonto a master information block (MIB), the master information block canbe mapped onto the broadcast control channel (BCCH) which is a logicalchannel, and the broadcast control channel can be mapped onto thebroadcast channel (BCH) which is a transport channel and the broadcastchannel can be further mapped onto the physical broadcast channel (PBCH)which is a physical channel to inform the parameter to the mobileterminals.

As an alternative, the parameter regarding the physical resource whichis identified in common can be mapped onto the broadcast control channel(BCCH) which is a logical channel, and the broadcast control channel canbe mapped onto a downlink shared channel (DL-SCH) which is a transportchannel and the downlink shared channel can be further mapped onto aphysical downlink shared channel (PDSCH) which is a physical channel toinform the parameter to the mobile terminals. The parameter regardingthe physical resource which is identified in common can be alternativelymapped onto system information and the system information can be mappedonto a system information block (SIB), the system information block canbe mapped onto the broadcast control channel (BCCH) which is a logicalchannel, and the broadcast control channel can be mapped onto thedownlink shared channel (DL-SCH) which is a transport channel and thedownlink shared channel can be further mapped onto the physical downlinkshared channel (PDSCH) which is a physical channel to inform theparameter to the mobile terminals. As an alternative, the parameterregarding the physical resource which is identified in common can bemapped onto a common control channel (CCCH), a dedicated control channel(DCCH), a multicast control channel (MCCH) or a multicast trafficchannel (MTCH), which is a logical channel, and this logical channel canbe mapped onto the downlink shared channel (DL-SCH) which is a transportchannel and the downlink shared channel can be further mapped onto thephysical downlink shared channel (PDSCH) which is a physical channel toinform the parameter to the mobile terminals.

As an another method, instead of informing the parameter regarding thephysical resource which is identified in common, the parameter regardingthe physical resource which is identified in common is predeterminedstatically (Static). Because it becomes unnecessary to inform theparameter from the network side to each mobile terminal by using theradio resources, there can be provided an advantage of making effectiveuse of the radio resources, and so on. Furthermore, because no radioresource is used for the transmission, there can also be provided anadvantage of preventing receiving errors from occurring. As an anothermethod, instead of informing the parameter regarding the physicalresource which is identified in common, the base station maps prescribedinformation (or a symbol) onto a physical radio resource of a part ofthe PMCH. Accordingly, each mobile terminal detects the physicalresource onto which the system information is mapped by carrying outblind detection of the physical radio resource with the prescribedinformation (or a symbol). Because the position of the mapping of thephysical resource can be changed without informing the parameter fromthe network side to each mobile terminal, there can be provided anadvantage of being able to use the radio resources with a high degree offlexibility.

Next, a concrete example of a method of, in the case in which the systeminformation is mapped physically, multiplexing an area of the PMCH ontowhich the system information is mapped and an area of the PMCH ontowhich the system information is not mapped will be disclosed hereafter.Time division multiplexing (TDM) of the area of the PMCH onto which thesystem information is mapped and the area of the PMCH onto which thesystem information is not mapped is carried out. In this case, as aconcrete example of the parameter regarding the physical resource whichis identified in common, there can be considered a starting point (as aconcrete example, SFN, a subframe number, or a symbol number), a periodlength (as a concrete example, a number of radio frames, a number ofsubframes, or a number of symbols), etc. As a concrete example of themultiplexing, the system information can be mapped onto the leading twoOFDM symbols of each subframe of the physical resource allocated to thePMCH. As another multiplexing method, frequency division multiplexing(FDM) of the area of the PMCH onto which the system information ismapped and the area of the PMCH onto which the system information is notmapped can be carried out. In this case, as a concrete example of theparameter regarding the physical resource which is identified in common,there can be considered a frequency, a bandwidth, etc. As a concreteexample of the multiplexing, the system information can be mapped onto anumber of subcarriers at the center of the physical resource allocatedto the PMCH. As an alternative, the system information can be mappedonto a number of subcarriers at an end of the physical resourceallocated to the PMCH. As another multiplexing method, code divisionmultiplexing (CDM) of the area of the PMCH onto which the systeminformation is mapped and the area of the PMCH onto which the systeminformation is not mapped can be carried out. In this case, as aconcrete example of the parameter regarding the physical resource whichis identified in common, there can be considered a spreading code, ascrambling code, etc. As a concrete example of the multiplexing, thearea of the PMCH onto which the system information is mapped and thearea of the PMCH onto which the system information is not mapped can bemultiplied by scrambling codes respectively. As an alternative, only oneof the areas can be multiplied by a scrambling code.

As another solution, the MBMS dedicated cell maps the system informationonto master information to transmit the system information to mobileterminals being served thereby. At that time, the MBMS dedicated cellcan map the system information as an information element of the masterinformation, or can map the system information physically. In the caseof mapping the system information physically, the MBMS dedicated cellneeds to map the system information onto a physical resource which isidentified in common by the network side and the UE side. Theabove-mentioned method disclosed for the case of mapping the parameteronto the PMCH to inform the parameter can be used as a method ofinforming the parameter regarding the physical resource which isidentified in common by the network side and the UE side. Furthermore,as a concrete example of a method of, in the case in which the systeminformation is mapped physically, multiplexing an area of the masterinformation onto which the system information is mapped and an area ofthe master information onto which the system information is not mapped,the above-mentioned method disclosed for the case of mapping the areasonto the PMCH to transmit the system information.

As another solution, a new channel is disposed, and the MBMS dedicatedcell maps the system information onto the above-mentioned new channel totransmit the system information to mobile terminals being servedthereby. The new channel is transmitted via a multi-cell transmissionscheme. Accordingly, there can be provided an advantage of making itpossible for each mobile terminal to carry out SFN combining, therebyimproving the reception quality of the system information by each mobileterminal. The new channel can exist in an MBSFN subframe. In the newchannel, it is necessary to map the system information onto a physicalresource different from the PMCH which is identified in common by thenetwork side and the UE side. The above-mentioned method disclosed forthe case of mapping the parameter onto the PMCH to inform the parametercan be used as a method of informing the parameter regarding thephysical resource which is identified in common by the network side andthe UE side. Furthermore, as a concrete example of a method of, in thecase in which the system information is mapped physically, multiplexingan area onto which the system information is mapped and an area ontowhich the system information is not mapped, the above-mentioned methoddisclosed for the case of mapping the areas onto the PMCH to transmitthe system information. The above-mentioned new channel will be referredto as a control channel (PMCCH) for physical multi-transmission fromhere on.

As the PMCCH, the same physical resource as that used by each of aunicast cell and an MBMS/unicast-mixed cell when transmitting an L1/L2control signal can be used. The physical channel of the MBMS dedicatedcell can be made to be similar to that of each of the unicast cell andthe MBMS/unicast-mixed cell, and there can be provided an advantage ofbeing able to avoid the complexity of the mobile communication system.As a concrete example, the MBMS dedicated cell transmits the PMCCH ineach subframe. As an alternative, the MBMS dedicated cell can transmitthe PMCCH with the leading one to three OFDM symbols of each subframe.The MBMS dedicated cell can alternatively transmit the PMCCH with theleading one or two OFDM symbols of each subframe. The MBMS dedicatedcell can multiply each information mapped onto the PMCCH by anidentifier specific to the type of the information. As a concreteexample, a case in which the MBMS dedicated cell transmits the systeminformation and other control information by using the PMCCH will beconsidered. The MBMS dedicated cell multiplies the system information byan identifier for the system information and also multiplies the othercontrol information by an identifier for the other control information,and then transmits them by using the PMCCH. A mobile terminal whichneeds to receive the system information, among the mobile terminalsbeing served by the MBMS dedicated cell, carries out blind detection byusing the identifier for the system information. Furthermore, a mobileterminal which needs to receive the other control information, among themobile terminals being served by the MBMS dedicated cell, carries outblind detection by using the identifier for the other controlinformation. As a result, there can be provided an advantage of enablingsuch a mobile terminal to receive required information when the mobileterminal requires the information. Accordingly, there can be provided anadvantage of reducing the power consumption of the mobile terminal.There can be provided a further advantage of preventing a control delaytime from occurring in the mobile terminal. The above-mentioned methodof informing the parameter regarding the physical resource which isidentified in common which is disclosed for the case of mapping theparameter onto the PMCH to inform the parameter can be used as a methodof informing the identifier for each of the information types.Furthermore, the method of informing the identifier for each of theseinformation types is not limited this embodiment, and can be applied toa case of using an identifier for each information type.

Information mapped onto an L1/L2 control signal in each of the unicastcell and the MBMS/unicast-mixed cell is multiplied by an identifier ofthe mobile terminal which is the destination to which the information isto be transmitted. A mobile terminal which needs to receive the L1/L2control signal, among mobile terminals being served by each of theunicast cell and the MBMS/unicast-mixed cell, carries out blinddetection by using the identifier of the mobile terminal. As a result,the mobile terminal acquires the necessary information from the L1/L2control signal. On the other hand, it has been examined that no uplinkchannel exists in the MBMS dedicated cell. Therefore, the MBMS dedicatedcell has no independent function of getting to know which mobileterminal belongs thereto as a mobile terminal being served thereby.Accordingly, there arises a problem that it is impossible to multiplythe information which the MBMS dedicated cell maps onto the PMCCH by anidentifier of a mobile terminal. Therefore, there arises a problem thateach mobile terminal cannot acquire the necessary information bycarrying out blind detection of the PMCCH by using the identifier of themobile terminal.

A solution of this problem will be disclosed hereafter. The MBMSdedicated cell gets to know which mobile terminal belongs to the MBMSdedicated cell, an MBSFN area, or an MBSFN synchronization area as amobile terminal being served by the MBMS dedicated cell, the MBSFN area,or the MBSFN synchronization area, and multiplies the information mappedonto the PMCCH by the identifier of a mobile terminal specified thereby.As a concrete example of how to get to know which mobile terminalbelongs to the MBMS dedicated cell, an MBSFN area, or an MBSFNsynchronization area as a mobile terminal being served by the MBMSdedicated cell, the MBSFN area, or the MBSFN synchronization area, anMBMS receiving state notification method, as described in Embodiment 2and so on, which a mobile terminal uses to notify an MBMS receivingstate to a serving cell in a unicast cell or an MBMS/unicast-mixed cellis used. The system information transmitted from the MBMS dedicated cellto mobile terminals being served by the MBMS dedicated cell, the MBSFNarea, or the MBSFN synchronization area by using either one of theabove-mentioned methods can be repeatedly broadcast at fixed periods. Asan alternative, a part of the system information can be repeatedlybroadcast at fixed periods. Master information (MIB) can bealternatively transmitted from the MBMS dedicated cell to mobileterminals being served by the MBMS dedicated cell, the MBSFN area, orthe MBSFN synchronization area by using either one of theabove-mentioned methods. By either one of the above-mentioned methods,there can be provided an advantage of establishing the method oftransmitting the system information from the MBMS dedicated cell tomobile terminals being served by the MBMS dedicated cell, the MBSFNarea, or the MBSFN synchronization area. Also in this embodiment, likein the case of Embodiment 2, the method of including, as identifiers ofeach mobile terminal, a mobile terminal identifier used in aunicast/mixed frequency layer and a mobile terminal identifier used in afrequency layer dedicated to MBSFN transmission can be used.

Next, variant 1 of this embodiment will be explained. MCCH scheduling ofthe MBMS dedicated cell, as described in Embodiment 2 and so on, can beinformed from the MBMS dedicated cell to mobile terminals being servedby the MBMS dedicated cell by using the above-mentioned method. The MCCHscheduling of the MBMS dedicated cell can be alternatively mapped ontobroadcast information (BCCH) of the MBMS dedicated cell, and can beinformed from the MBMS dedicated cell to the mobile terminals beingserved by the MBMS dedicated cell by using the above-mentioned method.The MCCH scheduling of the MBMS dedicated cell can be alternativelymapped onto the system information of the MBMS dedicated cell, and canbe informed from the MBMS dedicated cell to the mobile terminals beingserved by the MBMS dedicated cell by using the above-mentioned method.The MCCH scheduling of the MBMS dedicated cell can be alternativelymapped onto SIB2 of the MBMS dedicated cell, and can be informed fromthe MBMS dedicated cell to the mobile terminals being served by the MBMSdedicated cell by using the above-mentioned method. The MCCH schedulingof the MBMS dedicated cell can be alternatively mapped onto MIB of theMBMS dedicated cell, and can be informed from the MBMS dedicated cell tothe mobile terminals being served by the MBMS dedicated cell by usingthe above-mentioned method. As a result, there can be provided anadvantage of establishing the method of transmitting the MCCH schedulingfrom the MBMS dedicated cell to the mobile terminals being served by theMBMS dedicated cell.

Embodiment 28

It is described in nonpatent reference 6 (Chapter 6.10.2.1) that whendetermining the start position of OFDM symbols for a cell-specificreference signal (Reference signal), i.e., the start position ofmapping, a cell ID (N cell ID) is used. An N cell ID is defined as aphysical layer cell identity (Physical Layer cell identity). On theother hand, the reference has a description about an MBSFN referencesignal (MBSFN reference signal) in an MBSFN subframe. It is alsodescribed that an MBSFN area ID (N MBSFN ID) is used when determiningthe start position of OFDM symbols for a reference signal, i.e., thestart position of mapping. Furthermore, it is described in nonpatentreference 7 (Chapter 5.2.2.9) that a base station informs a setting ofMBSFN subframes to mobile terminals being served thereby with a systeminformation block 2 (SIB2) in system information included in broadcastinformation. In contrast, this reference does not have any descriptionabout an MBSFN area ID. The following problems arise in the conventionaltechnology.

Each mobile terminal cannot grasp the symbol position of an MBSFNreference signal in an MBSFN subframe at the time when it has receivedthe broadcast information of a serving cell. This is because an MBSFNarea ID is needed for the determination of the start position of OFDMsymbols of the MBSFN reference signal. That is, in order for each mobileterminal to grasp the position of the reference signal in the MBSFNsubframe, the use of only a conventional cell ID is not enough and anMBSFN area ID specific to the MBSFN subframe is needed. Therefore, thisproblem is specific to MBSFN. This results in a problem that each mobileterminal cannot carry out a correct measurement of the quality ofreception by using the MBSFN reference signal in the MBSFN subframe atthe time when it has received the broadcast information of the servingcell. This problem is specific to a mobile communication system havingMBSFN subframes. In other words, the problem is specific to a mobilecommunication system having a time period during which multi-celltransmission is carried out. Therefore, the problem is the newly-arisingone which has not arisen in conventional mobile communication systems.

Furthermore, there arises another problem as will be mentioned below.MBMS data are transmitted with a radio resource excluding the MBSFNreference signal in the MBSFN subframe. Therefore, each mobile terminalcannot grasp an OFDM symbol used for the transmission of the MBMS data(an MCCH and an MTCH) with the MBSFN subframe at the time when it hasreceived the broadcast information of the serving cell. Therefore, therearises a problem that each mobile terminal cannot receive an MBMSservice with MBSFN subframes at the time when it has received thebroadcast information of the serving cell.

A solution of the above-mentioned problem will be disclosed hereafter. Abase station informs an MBSFN area ID with broadcast information tomobile terminals being served thereby. As a concrete example of the basestation, a unicast cell or an MBMS/unicast-mixed cell can be provided.This method can also be applied to an MBMS dedicated cell. As a concreteexample of the MBSFN area ID, the ID of an MBSFN area to which theself-cell belongs can be provided. In a case in which the self-cellbelongs to a plurality of MBSFN areas, a plurality of MBSFN area IDs canbe transmitted to mobile terminals being served by the cell. As aconcrete example of the transmission, the MBSFN area ID of the self-cellcan be mapped onto a broadcast control channel (BCCH) which is a logicalchannel, and the broadcast control channel is mapped onto a broadcastchannel (BCH) which is a transport channel and the broadcast channel isfurther mapped onto a physical broadcast channel (PBCH) which is aphysical channel to transmit the MBSFN area ID of the self-cell to themobile terminals. As an alternative, the MBSFN area ID of the self-cellcan be mapped onto master information and the master information can bemapped onto a master information block (MIB), the master informationblock can be mapped onto the broadcast control channel (BCCH) which is alogical channel, and the broadcast control channel can be mapped ontothe broadcast channel (BCH) which is a transport channel and thebroadcast channel can be further mapped onto the physical broadcastchannel (PBCH) which is a physical channel to transmit the MBSFN area IDof the self-cell to the mobile terminals. The information mapped on thephysical broadcast channel is received by all the mobile terminals beingserved by the serving cell before each of the mobile terminals camps onthe serving cell, or at an earlier time after each of the mobileterminals camps on the serving cell. Therefore, this solution canprovide an advantage of being able to start a correct measurement of thequality of reception using the MBSFN reference signal in the MBSFNsubframe, and reception of an MBMS service with MBSFN subframes at anearlier time. That is, there can be provided an advantage of preventinga control delay time from occurring.

Another solution will be disclosed hereafter. A base station informs anMBSFN area ID with broadcast information to mobile terminals beingserved thereby. As a concrete example of the base station, a unicastcell or an MBMS/unicast-mixed cell can be provided. This method can alsobe applied to an MBMS dedicated cell. As a concrete example of the MBSFNarea ID, the ID of an MBSFN area to which the self-cell belongs can beprovided. In a case in which the self-cell belongs to a plurality ofMBSFN areas, a plurality of MBSFN area IDs can be transmitted to mobileterminals being served by the cell. As a concrete example of thetransmission, the MBSFN area ID of the self-cell can be mapped onto abroadcast control channel (BCCH) which is a logical channel, and thebroadcast control channel is mapped onto a downlink shared channel(DL-SCH) which is a transport channel and the downlink shared channelcan be further mapped onto a physical downlink shared channel (PDSCH)which is a physical channel to transmit the MBSFN area ID of theself-cell to the mobile terminals. As an alternative, the MBSFN area IDof the self-cell can be mapped onto system information and the systeminformation can be mapped onto a system information block (SIB), thesystem information block can be mapped onto the broadcast controlchannel (BCCH) which is a logical channel, and the broadcast controlchannel can be mapped onto the downlink shared channel (DL-SCH) which isa transport channel and the downlink shared channel can be furthermapped onto the physical downlink shared channel (PDSCH) which is aphysical channel to transmit the MBSFN area ID of the self-cell to themobile terminals. As an alternative, the MBSFN area ID of the self-cellcan be mapped onto SIB2 in a system information block and the SIB2 canbe mapped onto the broadcast control channel (BCCH) which is a logicalchannel, and the broadcast control channel can be mapped onto thedownlink shared channel (DL-SCH) which is a transport channel and thedownlink shared channel can be further mapped onto the physical downlinkshared channel (PDSCH) which is a physical channel to transmit the MBSFNarea ID of the self-cell to the mobile terminals.

This solution can provide the following advantages. The setting of MBSFNsubframes is broadcast by using the SIB2 as mentioned above. Therefore,each mobile terminal becomes able to acquire the “setting of MBSFNsubframes” and the “MBSFN area ID” which are the information requiredfor a correct measurement of the quality of reception using the MBSFNreference signal in the MBSFN subframe through the reception of the samesystem information block. Accordingly, there can be provided anadvantage of being able to avoid the complexity of the measurementoperation of correctly measuring the quality of reception using theMBSFN reference signal in the MBSFN subframe which is performed by eachmobile terminal. This results in another advantage of preventing acontrol delay time from occurring. Furthermore, each mobile terminalbecomes able to acquire the “setting of MBSFN subframes” and the “MBSFNarea ID” which are the information required for the reception of MBMSdata with MBSFN subframes through the reception of the same systeminformation block. Accordingly, there can be provided an advantage ofbeing able to avoid the complexity of the operation of receiving MBMSdata with MBSFN subframes which is performed by each mobile terminal.This results in another advantage of preventing a control delay timefrom occurring.

Another solution will be disclosed hereafter. A base station informs anMBSFN area ID with broadcast information to mobile terminals beingserved thereby. As a concrete example of the base station, a unicastcell or an MBMS/unicast-mixed cell can be provided. This method can alsobe applied to an MBMS dedicated cell. As a concrete example of the MBSFNarea ID, the ID of an MBSFN area to which the self-cell belongs can beprovided. In a case in which the self-cell belongs to a plurality ofMBSFN areas, a plurality of MBSFN area IDs can be transmitted to mobileterminals being served by the cell. As a concrete example of thetransmission, the MBSFN area ID of the self-cell can be mapped onto acommon control channel (CCCH) or a dedicated control channel which is alogical channel, and the common control channel or dedicated controlchannel is mapped onto a downlink shared channel (DL-SCH) which is atransport channel and the downlink shared channel can be further mappedonto a physical downlink shared channel (PDSCH) which is a physicalchannel to transmit the MBSFN area ID of the self-cell to the mobileterminals. This solution can provide an advantage of being able to carryout a correct measurement of the quality of reception using the MBSFNreference signal in the MBSFN subframe, and reception of an MBMS servicewith MBSFN subframes while providing control featuring high flexibilityfor the mobile communication system.

Embodiment 29

In a case in which the system bandwidth of a cell in a frequency layerdedicated to MBMS is broadcast from an MBMS dedicated cell, the systembandwidth has to be transmitted via a multi-cell transmission schemebecause multi-cell transmission has to be carried out in the MBMSdedicated cell in an MBSFN area. Therefore, there arises a problem thatin MBMS dedicated cells in an MBSFN area, their system bandwidths haveto be the same as one another. In order to solve the above-mentionedproblem, in this embodiment, a cell which carries out multi-celltransmission broadcasts the widest one of system bandwidths to mobileterminals being served thereby by using broadcast information. Aconcrete example will be shown. All cells in an MBSFN area broadcaststhe same system bandwidth by using broadcast information. In this case,the same system bandwidth broadcast is the widest one of the systembandwidths of the cells in the MBSFN area. The system bandwidthinformation is mapped onto MIB as system information, and is broadcastby using a PBCH. An example of the system bandwidth of each cell in anMBSFN area is shown in FIG. 102. Cells #n1-1 to #n1-3 are assumed toexist in the same MBSFN area. It is assumed that the cell #n1-1 has asystem bandwidth BW1, the cell #n1-2 has a system bandwidth BW2, and thecell #n1-3 has a system bandwidth BW3. The carrier frequencies of thecells are the same as one another. The system bandwidths of the cells inthe MBSFN area are set in this way. In this case, because the widest oneof the system bandwidths of the cells in the MBSFN area is BW3, BW3 istransmitted, as the system bandwidth information, from all the cells inthe MBSFN area to mobile terminals being served by the cells.

The widest one of the system bandwidths of the cells in the MBSFN areais determined by, for example, an MCE which manages the cells in theMBSFN area, and the MCE informs the widest system bandwidth to each ofthe cells in the MBSFN area. The MCE has only to acquire the systembandwidth information about each of all the cells in the MBSFN area inadvance. When each of the cells is installed in the MBSFN area, thesystem bandwidth information about the cell can be stored in the MCE. Asan alternative, each of the cells in the MBSFN area can transmit thesystem bandwidth information about the self-cell to the MCE in advance,and the MCE can determine the widest one of the system bandwidths of thecells in the MBSFN area. When each of the cells is installed in theMBSFN area, the system bandwidth information about the cell can betransmitted to the MCE. An example of a method of broadcasting thesystem bandwidth from each cell to mobile terminals being served by thecell in this case is shown in FIG. 103. In this figure, a method oftransmitting the system bandwidth information about each cell in theMBSFN area from the cell to the MCE in advance, and making the MCEdetermine the widest one of the system bandwidths of the cells in theMBSFN area is shown. Each of the MBMS dedicated cells #n1-1, #n1-2 and#n1-3 in the MBSFN area, in steps ST5001, ST5002, and ST5003, transmitsthe system bandwidth information about the self-cell to the MCE. The MCEwhich, in steps ST5004, ST5005, and ST5006, receives the systembandwidth information from each of all the cells in the MBSFN area, instep ST5007, derives the widest one of the system bandwidths in thisMBSFN area on the basis of the above-mentioned system bandwidthinformation. The MCE, in step ST5008, transmits the widest systembandwidth information derived in the MBSFN area to all the cells in theMBSFN area. Each of the cells which, in step ST5009, receives the widestsystem bandwidth information in the MBSFN area, insteps ST5010, ST5011,and ST5012, broadcasts, as system information from each of the cells,the widest system bandwidth information in the MBSFN area to the mobileterminals being served thereby.

Each of the mobile terminals which, in step ST5013, receives the systembandwidth information carries out reception at this system bandwidth.Each of the mobile terminals performs SFN combining on a signaltransmitted from an MBMS dedicated cell in the MBSFN area when receivingthis signal because it is transmitted via an MC transmission scheme.Therefore, even if the system bandwidths of the cells in the MBSFN areadiffer from one another, each of the mobile terminals becomes able toperform SFN combining on a transmission signal from each cell in theMBSFN area because each mobile terminal is made to receive thetransmission signal at the widest system bandwidth in the MBSFN area.For example, in the example of FIG. 102, when receiving a transmissionsignal having the bandwidth BW2, each of the mobile terminals performsSFN combining of transmission signals from the cells #n1-1, #n1-2, and#n1-3, when receiving a transmission signal having the bandwidth BW1,each of the mobile terminals performs SFN combining of transmissionsignals from the cells #n1-1 and #n1-3, and when receiving atransmission signal having the bandwidth BW3, each of the mobileterminals performs SFN combining of only a transmission signal from thecell #n1-3. For example, in an LTE system, because a frequency band atthe center in the system band is used for an SCH for synchronizationestablishment or a PBCH for broadcast information transmission in eachcell, the frequency band is informed in common from all the cells. Thecells can be arranged in such a way that for example, the cell havingthe widest system bandwidth is arranged as a macro cell having a widecoverage area, and the other cells having narrower system bandwidths(e.g., a micro cell, a pico cell, a femto cell, a home base station, andso on) are arranged in adjacent areas of the above-mentioned macro cell.In accordance with a method of using frequencies in the MBSFN area, forexample, bandwidths at both ends (e.g., BW3 and BW1) can be allocated tomobile terminals existing in the vicinity of the macro cell, and abandwidth in the middle (e.g., BW1 or BW2) can be allocated to mobileterminals each existing in the vicinity of a narrow-band cell at adistant from the macro cell. By using this method configured in thisway, because the SFN gain of a mobile terminal existing in the vicinityof the macro cell can be improved, the quality of reception of themobile terminal can be improved.

By using the method disclosed in this embodiment, there is no necessityto make the system bandwidths of all cells which construct an MBSFN areabe the same as one another, and therefore the system bandwidths of allthe cells can be made to differ from one another. Therefore, becauseeach cell can be arranged with flexibility and flexible arrangement ofcells having different system bandwidths can improve the SFN gain ofeach mobile terminal, there is provided an advantage of improving thecommunication quality of the system. These methods can be applied alsoto a home base station or the like which is placed in a macro cell. Inabove-mentioned embodiment, cells in an MBSFN area are shown as aconcrete example. However, this embodiment is not limited to cells in anMBSFN area, and can be applied to cells each of which carries outmulti-cell (MC) transmission.

The invention claimed is:
 1. A communication system which uses anorthogonal frequency division multiplexing (OFDM) method as a downlinkaccess method from a base station to a mobile terminal and uses a singlecarrier-frequency division multiple access (SC-FDMA) method as an uplinkaccess method from the mobile terminal to the base station, the basestation and mobile terminal being included in the communication system,the communication system comprising: a plurality of multimedia broadcastmulticast service single frequency network (MBSFN} areas each configuredto provide multimedia broadcast multicast service (MBMS) on a singlefrequency, each MBSFN area including multiple cells, wherein the basestation belongs to the plurality of MBSFN areas and is configured totransmit each MBSFN area identification (ID) of the plurality of MBSFNareas by a broadcast control channel (BCCH), the mobile terminal isconfigured to receive each MBSFN area ID of the plurality of MBSFN areasby the BCCH; and wherein each of a multicast control channel (MCCH) anda multicast traffic channel (MTCH) for each of the plurality of theMBSFN areas is multiplied by a scrambling code related to each MBSFNarea ID of the plurality of MBSFN areas.
 2. A base station used in acommunication system which provides multimedia broadcast multicastservice (MBMS), wherein the base station is configured to belong to aplurality of multimedia broadcast multicast service single frequencynetwork (MBSFN) areas in each of which the MBMS is provided on a singlefrequency, each of the MBSFN areas including multiple cells, wherein thebase station is adapted to transmit each MBSFN area identification (ID)of the plurality of MBSFN areas by a broadcast control channel (BCCH),and wherein each of a multicast control channel (MCCH} and a multicasttraffic channel (MTCH} for each of the plurality of the MBSFN areas ismultiplied by a scrambling code related to each MBSFN area ID of theplurality of MBSFN areas.
 3. A mobile terminal used in a communicationsystem which provides multimedia broadcast multicast service (MBMS),wherein the mobile terminal is configured to receive each multimediabroadcast multicast service single frequency network (MBSFN) areaidentification (ID) of a plurality of MBSFN areas that each includemultiple cells by a broadcast control channel (BCCH) transmitted from abase station belonging to the plurality of MBSFN areas in each of whichthe MBMS is provided on a single frequency, and wherein each of amulticast control channel (MCCH) and a multicast traffic channel (MTCH)for each of the plurality of the MBSFN areas is multiplied by ascrambling code related to each MBSFN area ID of the plurality of MBSFNareas.